The Dell Windows Reinstallation Guide is an unofficial set of installation guides written and maintained by an individual Philip Yip. To support the running costs of this site, as well as the costs of test hardware needed to keep the guides up to date. Please consider leaving a donation or clicking on the affiliate link if you are planning on buying Office or a SSD Upgrade for your system anyway. I'd like to thank you in advance for leaving any donations or clicking on the affiliate links. Written in Scotland , Great Britain (GB), , United Kingdom (UK) and hopefully soon to be part of Canada, Australia, New Zealand and the United Kingdom (CANZUK).

Download Windows 7 SP1 Commercial OEM and Retail .iso



Obsolete Guide – Please See Updated Guide Creating Up to Date Windows 7 Installation Media

Tutorial Video

Written Guide January 2020

Windows 7 Reached End of Mainstream Support in January 2015. Extended Support lasts until January 2020. For more details see End of Support.


Your Windows 7 OEM or Retail License is eligible for a Free Upgrade to Windows 10 for more details see Windows OEM FAQs and Downloads.


Windows 7 SP1 – Retail and Commercial OEM Download Links

For Dell Systems updated Dell Windows Pro 7 January 2016 Reinstallation .isos are recommended.

The Windows 7 November 2011 .isos from Microsoft are unbranded and can be used with any Windows 7 OEM or Retail License. For OEM Licenses one may skip the product key during installation to begin a 30 day trial and apply their manufacturers OEM SLP post installation to activate Windows 7. Microsoft’s software download page for Windows 7 is however unfortunately non-functional in most cases.

Jan Krohn’s Microsoft Windows and Office .iso Downloader Tool is a utility that essentially fixed the flawed user interface of Microsoft’s software download page allowing the generation of proper download links.

Note the installation media created in this guide will be multi-edition including Starter (32 Bit only), Home Basic, Home Premium, Professional and Ultimate and work with all OEM and Retail licenses:

  • It therefore does not matter if you select a Commerical OEM .iso or a Retail .iso.
  • It also doesn’t matter what Edition of Windows 7 you select.

English File Sizes and Checksums

For Windows 7 – English UK and English US are the same “Language”.

The time and currency format and keyboard or input method can be selected for English UK (International English) or English US respectively:


The Microsoft Windows and Microsoft .iso Downloader Tool generates direct download links from Microsoft’s servers. It doesn’t check whether the .iso you downloaded is complete or not.

For the English .isos the file size is 2,504,372 KB for Windows 7 32 Bit and 3,243,070 KB for Windows 7 64 Bit.

The checksums can be checked with Rufus (which we will use later to make the Bootable USB):

Rufus doesn’t need to be installed. Launch Rufus:

Accept the User Account Control:

Select “Select”:

Select your installation .iso and select open:

Select the tick:

Rufus will now compute the .iso checksums:

Just use the MD5. For an English .iso on this page press [Ctrl] and [ f ] and paste the checksums. Ensure that they match one of the values below:

If there is no match your .iso is unique and thus corrupt. For other languages a google search should suffice to make sure you have a non-unique .iso.

Commerical OEM .isos

Win7_Starter_SP1_English_COEM_x32 (2,504,372 KB)

  • MD5: c23c9cecee7e3093acfe00faab7091b5
  • SHA1: e1653b111c4c6fd75b1be8f9b4c9bcbb0b39b209
  • SHA256: a1cd61a1731b1deeda089c823c815454cb7a7de04b2b7f0cd4c171e31afb61b2

Win7_HomeBasic_SP1_English_COEM_x32.iso (2,504,372 KB)

  • MD5: f760d5a0ed615c6a93829ebc84db2a0d
  • SHA1: c1e663fa5138ccb08e07ccc5bab1d74d168e3452
  • SHA256: e63637b39caf187ee3f7dd68c51cc0509157d58c498002933735992760fa4dfb

Win7_HomeBasic_SP1_English_COEM_x64.iso (3,243,070 KB)

  • MD5: b650412b04de41f36a53ef7e0658a8b3
  • SHA1: 72666801e3ce687625173a11e1a3e7ffed04f148
  • SHA256: e2764cf9c06fc51e4f556bb6675a840d0e8e6bd507c938caac4ebccdf0ad771b

Win7_HomePrem_SP1_English_COEM_x32 (2,504,372 KB)

  • MD5: ec49e3869291f2dc0aae53c21f3ac51a
  • SHA1: f0991cbdbf87d54c3bf97e189f7a4a5aba692a59
  • SHA256: 653c2a494f19c06ce33c9e0bec29ae2d07a0a736aa1712e87391126d64444047

Win7_HomePrem_SP1_English_COEM_x64 (3,243,070 KB)

  • MD5: 1bfe92baeadf28092557ed80376938f9
  • SHA1: 1e0cdfafb6a390e0e7e9f54ce99395ee42a59de0
  • SHA256: 1dd79367c866573efd2de02ce331bac93a67d3395474d6911d2b28444d5ee3c0

Win7_Pro_SP1_English_COEM_x32 (2,504,372 KB)

  • MD5: 296f892e1f9b66ef5836a54557309e94
  • SHA1: a908cf84fd448c235945fb5b6e2ff232eb362575
  • SHA256: f814b85295351e4ab902dc1777c5539f6d855c8997bea833277290bca0a5385b

Win7_Pro_SP1_English_COEM_x64 (3,243,070 KB)

  • MD5: 39134fad6ccc6292a5e81a5dcedc4d13
  • SHA1: 5998495086fde086b2c8a1e490d8f1cd1dcc99cc
  • SHA256: 8341417c575adb92cd11a1f77666b6d6cbbcfc56855927407235983e838cfe83

Win7_Ult_SP1_English_COEM_x32 (2,504,372 KB)

  • MD5: 02f83c24906fe8b8308cf21af7f39f0e
  • SHA1: c511bf0de7632c47e8a2071acfe04637b498212d
  • SHA256: ad3a17fbbd513083adf49606bd9779c561071837b04f5bf6b3d0ea2ea0c39407

Win7_Ult_SP1_English_COEM_x64 (3,243,070 KB)

  • MD5: b00ccf47143f62486cecf467850e6c33
  • SHA1: 37a6ed40d14428617c8fa196ec5448478db63bb9
  • SHA256: 9a7ac3bad825996a3ef3b9efc0a8b9750961b730c5aab3df64a9fd10a6ba02f4

Retail .isos

Win7_HomeBasic_SP1_English_x32 (2,504,372 KB)

  • MD5: 706c0eb93af2fb3df98e22422c72182c
  • SHA1: 080ec1de94b88b0f7e8d000690a4aaaa031e2719
  • SHA256: d8fa5ea8cf67315fa6ce693ef0c70503df7e14258301585ebc28eb1c6c8d6216

Win7_HomePrem_SP1_English_x32 (2,504,372 KB)

  • MD5: 0afa9359c62dc7b320205d3863c60385
  • SHA1: 6071b4553fcf0ea53d589a846b5ae76743dd68fc
  • SHA256: fe504356ac617baa572826a6fbf9ecba07cc498b3b79fcc6294a487f81fdd8e7

This .iso was called X17-58996.iso when it was hosted on Digital River before February 2015.

Win7_HomePrem_SP1_English_x64 (3,243,070 KB)

  • MD5: da319b5826162829c436306bebea7f0f
  • SHA1: 6c9058389c1e2e5122b7c933275f963edf1c07b9
  • SHA256: c10a9da74a34e3ab57446cddd7a0f825d526da78d9796d442db5022c33e3cb7f

This .iso was called X17-58997.iso when it was hosted on Digital River before February 2015.

Win7_Pro_SP1_English_x32 (2,504,372 KB)

  • MD5: 0bff99c8310ba12a9136e3d23606f3d4
  • SHA1: d89937df3a9bc2ec1a1486195fd308cd3dade928
  • SHA256: fd4cdf56e0087ac4a76d6858046f3ee50977d47917ca96366322e271ddd4838e

This .iso was called X17-59183.iso when it was hosted on Digital River before February 2015.

Win7_Pro_SP1_English_x64 (3,243,070 KB)

  • MD5: ed15956fe33c13642a6d2cb2c7aa9749
  • SHA1: 0bcfc54019ea175b1ee51f6d2b207a3d14dd2b58
  • SHA256: 3dae1a531b90fa72e59b4a86b20216188d398c8c070da4a5c5a44fe08b1b6e55

This .iso was called X17-59186.iso when it was hosted on Digital River before February 2015.

Win7_Ult_SP1_English_x32 (2,504,372 KB)

  • MD5: 2572274e6b0acf4ed1b502b175f2c2db
  • SHA1: 65fce0f445d9bf7e78e43f17e441e08c63722657
  • SHA256: e2c009a66d63a742941f5087acae1aa438dcbe87010bddd53884b1af6b22c940

This .iso was called X17-59463.iso when it was hosted on Digital River before February 2015.

Win7_Ult_SP1_English_x64 (3,243,070 KB)

  • MD5: c9f7ecb768acb82daacf5030e14b271e
  • SHA1: 36ae90defbad9d9539e649b193ae573b77a71c83
  • SHA256: 36f4fa2416d0982697ab106e3a72d2e120dbcdb6cc54fd3906d06120d0653808

This .iso was called X17-59465.iso when it was hosted on Digital River before February 2015.

Note Windows 7 Starter is OEM only and hence not found as a Retail .iso. It is unknown why there is a 64 Bit and 32 Bit Commerical OEM .iso and only a 32 Bit Retail .iso for Windows 7 Home Basic. This Edition is pretty much OEM only however.

Checking if your System has an UEFI Boot

Power down your Dell and then power up and Press [F12]. For non-Dells you may have to use [Esc] or another Function key [F1-F12]. This will take you to your systems Boot Menu.

If it mentions at the top “Boot Mode" then you have a UEFI BIOS. For Windows 7 Installation:

  • The Boot Mode should be set to UEFI.
  • Secure Boot should be Off
  • Legacy ROMs settings (not shown on the Boot Manager Screen) should be Enabled.
  • Note that early UEFI systems may not have Secure Boot and hence no need for Legacy ROM Settings.

For details in Enabling these settings see Unified Extensive Firmware Interface (UEFI).

If it doesn’t mention at the top “Boot Mode" then you have an older system with a Legacy BIOS.

Creating a Bootable USB

Note all the data will be lost on your USB Flash Drive when you create a Windows 7 Bootable USB.

Insert a 8-32 GB USB Flash Drive, it’ll display under Device. If you have multiple USB flash drives attached ensure you select the correct device.

The Partition Scheme: Windows 7 64 Bit (2012-2016 Computer)

If you are installing Windows 7 64 Bit, the default settings will use the GPT Partition Scheme. GPT has the advantage that it contains multiple Boot Records opposed to a Single Boot Record, can support many more partitions (128 versus 4) and can work with larger drives (>2 TB). The Target System, File System and Cluster Size will be updated correspondingly.

It is advised to change the Partition Scheme from FAT32 to NTFS. FAT32 has the advantage that it can pass through Secure Boot, which Windows 7 cannot do anyway. NTFS can support file sizes >4 GB and your install.wim may be >4 GB if you follow my instructions to perform a slipstream.

The Partition Scheme: Windows 7 64 Bit (2007-2011 Computers) and Windows 7 32 Bit (2007-2016 Computers)

For earlier computers that don’t possess a UEFI BIOS you have have to change GPT to MBR. The Target System, File System and Cluster Size will be updated correspondingly. If you are using a Windows 7 32 Bit installation .iso you also have to use MBR but this will be automatically selected:

Creating the Bootable USB

Change the volume label to something more sensible like “Win7x64”:

Select “Start”:

You will get a warning about formatting your USB, select OK to proceed:

Rufus will make the Bootable USB:

When done it will say Ready at the bottom. Press close to close Rufus:

Adding Driver Support

The installation ISOs from Microsoft are unfortunately from 2011 and do not have support for USB 3.0 or many storage controllers. If you try and use it with hardware with these technologies you may get stuck here with a non-responsive keyboard or mouse:


Or alternatively here and get:

“A required CD\DVD drive device driver is missing. If you have a driver floppy disc, CD, DVD, or USB flash Drive, please insert it now. Note: If the Windows installation media is in the CD/DVD drive, you can safely remove it for this step.”


Moreover if you use a NVMe SSD you will get a constant BSOD after installation.

Windows 7 Update and Driver Slipstream Script

With Windows 7 Installation Media being from 2011, in addition to the driver support issues mentioned above, the time it takes to patch a Windows 7 install can take 2-3 times as long as the installation process of Windows 7 itself. I have made a Windows 7 Slipstream Script which slipstreams the Convenience Rollup and it’s perquisite updates, Internet Explorer 11 and it’s perquisite updates, the NVMe Hotfixes, Intel USB 3.0 Drivers, Intel F6 Storage Controllers and the latest Security Rollup for Windows 7 see Slipstreaming Windows 7. I have made the slipstreaming guide as easy to follow as possible but it is still fairly advanced and the alternative solution “Adding USB Drivers Using the Gigabyte Windows USB Tool” and then manually installing the Updates can be used instead (see below).

Adding USB Drivers Using the Gigabyte Windows USB Tool

To make your Bootable USB usable on up to 6th Generation Intel Skylake hardware you’ll need to add drivers to the Bootable USB.

The Windows USB Installation Tool by Gigabyte adds USB 3.0 drivers and storage controller drivers for Intel and Samsung NVMe SSDs as well as associated hotfixes. It may be found here:

Scroll down until you find it:

Alternatively press [Ctrl] and [ f ] and search for Windows USB Installation Tool.

Download the tool and extract it:

To launch the utility double click the WindowsImageTool.exe and accept the User Account Control:

Check the three boxes to add the drivers:

Leave the Source Path as “None – Add USB Drivers" and change the Destination Path to your Windows 7 Bootable USB Flash Drive:

Select Start:

The tool will mount each index of your boot.wim file, add the drivers and then commit the changes. It’ll repeat the process for the install.wim file:

For a Bootable USB made from a English Windows 7 64 Bit .iso Downloaded Directly from Microsoft.

The process took about 16 minutes in my test.

The boot.wim found in the sources folder of the USB was updated from 160 MB to 189 MB.

The install.wim found in the sources folder of the USB was updated from 2.75 GB to 2.88 GB.

Delete the EI.cfg file

The ei.cfg should be deleted after the Bootable USB is made to allow installation of all Editions of Windows 7 for a Corresponding Architecture.

Open up the USB in Windows Explorer go to the sources folder and look for ei.cfg and delete it.




During installation you will get the option to install your desired Edition of Windows 7:


Standalone Updates for Windows 7

It is highly advised to create an Updates folder on your Bootable USB and to download and place the following updates in it. Also make a text file in this folder and copy the information below so you know what order to install the updates in. Installing these updates immediately after Windows 7 will save you Windows Update hassles due to your installation media being >7 years out of date and embedded with Internet Explorer 8 which is no longer supported.

Windows 7 64 Bit

Service Stack and Convenience Rollup

A restart is required after each of these updates.

Perquisite IE11 Updates

A restart is required after each of these updates.


The Latest Security Rollup

A restart is required after this updates.

When downloading sort by the latest date, use the latest (non-preview) Windows 7 for x64-based systems update only.

Microsoft .Net Framework

Microsoft Security Essentials

Microsoft Security Essentials Latest Definition

Windows 7 32 Bit

Service Stack and Convenience Rollup

A restart is required after each of these updates.

Perquisite IE11 Updates

A restart is required after each of these updates.


The Latest Security Rollup

A restart is required after this updates.

When downloading sort by the latest date, use the latest (non-preview) Windows 7 for x64-based systems update only.

Microsoft .Net Framework

Microsoft Security Essentials

Microsoft Security Essentials Latest Definition

OEM Cert Collection

If you are using a system with an OEM License (including OEM Downgrade Rights from Windows 8.x Pro and Windows 10 Pro) on a computer manufacturered by a major OEM such as Dell, HP, Lenovo, ASUS, Acer, Compaq, Gateway, Packard, Fujitsu, IBM, MSI, Samsung, Sony or Toshiba you are best to install Windows 7 without a Product Key and activate post installation using OEM System Locked Preinstallation – the same BIOS based Product Activation mechanism of factory settings. Doing so will save you from having to call Microsoft to activate by phone.

I have put together the OEM Cert Collection along with an associated 2 line script to install the Cert and Apply the associated OEM SLP Key. After Installation copy the OEM folder containing the cert and OEM SLP key to your C:\ Drive and then run the script file.

It is available as a .zip file here.

Install Windows 7

To install Windows 7 see Windows 7 Installation in a UEFI BIOS or Legacy BIOS.

European Commission N English Checksums

Previously there were European Commission N Editions of Windows 7. These are slightly less functional Editions of Windows 7 created because the European Commission didn’t approve of Microsoft bundling Windows Media Player and Windows Media Centre in Windows 7. However like the European Commission they are extremely unpopular especially in the Anglosphere. The Windows iso Downloader no longer seems to list N Editions however in the off-chance they are shown you should avoid them as your Product Key is unlikely to work with them.

The European Commission is now wasting time with Article 13 trying to break the Internet a bit like Windows Vista and extreme User Account Control:

Commercial OEM N .isos

Win7_HomePrem_N_SP1_English_COEM_x32 (2,217,196 KB)

  • MD5: 9feb6e72e3d91cb581df4709a7fe1406
  • SHA1: b56d31708187d46bd70b14f5a0cbc601c7824967
  • SHA256: 39a8d7b6ede58c06182fa1692adbac627f5e812362093a261c17842584ff1bb5

Win7_HomePrem_N_SP1_English_COEM_x64 (2,904,836 KB)

  • MD5: 61fb17338ca579c9b88fb612f053042a
  • SHA1: 8ddd6461df488e1cf09d815dc931de7e9c0a391b
  • SHA256: d9845049002343327e2965ec7d48fc8c314b4a42261fe53b2707a1035edac9b9

Win7_Pro_N_SP1_English_COEM_x32 (2,217,196 KB)

  • MD5: 8f9dc4097d5530522f9daf848e4bcd29
  • SHA1: 05856ff8cb806c2226680015dc84ae32757afbee
  • SHA256: 8d390e8890ba812c4d07f6f76110325093f41b9132db3bec3a949513577be5e7

Win7_Pro_N_SP1_English_COEM_x64 (2,904,836 KB)

  • MD5: 0adeff47e09dd18b2fed976f5998a4ff
  • SHA1: 650d01efbb8bc06d96ad0ca39342dd56da6dc010
  • SHA256: 4c63c6acd2e58b965f93ebec419c3c375d46faef82314b12f40ba4df77ab69e6

Win7_Ult_N_SP1_English_COEM_x32 (2,217,196 KB)

  • MD5: 1a8802855b49fa691e26dbd95b6e7bcc
  • SHA1: cd836ac87671164dc6d574414ee860ac8680ddd8
  • SHA256: befb0c02070bf477b25652a11912cb28ba77f0a2822fa3323c9fc83fc8d6ec60

Win7_Ult_N_SP1_English_COEM_x64 (2,904,836 KB)

  • MD5: 016239e9d44a3494ad8a00ab8803959c
  • SHA1: ac688c494acdb6efe44f5dcad15810a094720ef3
  • SHA256: d6d4fca366b04cbeb83326e809265560416f27bd74509cfae5225a28a165bf7a

Retail N .isos

Win7_HomePrem_N_SP1_English_x32 (2,217,196 KB)

  • MD5: b5edcee4c7c851c13c064ecd7c7176e6
  • SHA1: f17fb1397797c5e83a3f18e76f19dcee2b0736d4
  • SHA256: daa5ff6bbaf4bade6c4bcd559ae7151e1d26281b38421ef1864a6e831436b7bc

Win7_HomePrem_N_SP1_English_x64 (2,904,836 KB)

  • MD5: 9d8ca8fec19272ce96f3728ccbd1db6b
  • SHA1: 6496c1221b4d2090ea599acafbee33aa6855aadc
  • SHA256: e9bdc2f18144bd44fab5fd4f8e963ad16b1f0e68708a0f091820c605dcac8a22

Win7_Pro_N_SP1_English_x32 (2,217,196 KB)

  • MD5: a553f87c6d4102ea317c8ede93891662
  • SHA1: fda90230e29052b7b20ca408e961c5d2743041f1
  • SHA256: ed70d0260e4c16da603e5364b4bdab4f681532a8094b15ac4d056610658e9b2e

Win7_Pro_N_SP1_English_x64 (2,904,836 KB)

  • MD5: 57de0ef0d8aec8f57648c41ca6dc855d
  • SHA1: 59f942bc69ca6d8ab25a3b63a018d86d8acee78b
  • SHA256: 7c9573f127e01c877d6d3f22bd3ba4bbfe8dbc421755697b679557c0850bd09b

Win7_Ult_N_SP1_English_x32 (2,217,196 KB)

  • MD5: 8d9c55270d91a25663517dbef9968c80
  • SHA1: bbf301280faa00b02f5475cdaa06558f569569e8
  • SHA256: 12da8abb86ca0651ecc919bf342d7990b1175ef2eb3a22e3bfbcfa38f770c7a5

Win7_Ult_N_SP1_English_x64 (2,904,836 KB)

  • MD5: 125a15247bceb880d6ae6a30e481eeb2
  • SHA1: e01a55499fe9eba718b59492e55b567f3d6f4e1b
  • SHA256: 24e6a5719cf8ed3b0afda7c21f989cbf93ed627c1ef99ba3359010fc1132901f

111 thoughts on “Download Windows 7 SP1 Commercial OEM and Retail .iso

  1. There is a mistake in the text, because links for professional and ultimate edition x64 lead to same URL (for Ultimate edition)…

    1. You need to purchase a product key or you can install without one for a 30 day trial.

      If you have a system which came with Windows 7 Home Premium OEM preinstalled e.g. from Dell there should be a COA affixed to the system (maybe in the battery compartment of laptops or computer cover of desktops).

      For more details see Windows Reinstallation Guide/A Clean install of Windows 7:

      You can purchase a retail/OEM Windows 7 Home Premium license from the likes of NewEgg, Amazon etc. and input the product key provided to activate.

  2. I’m going to use your files and tutorials to do clean installs of windows 7 on (3) oem machines this weekend (all machines have windows 7 COA stickers). I figured clean installs are going to be MUCH faster than installing via the oem recovery media, which puts a massive amount of bloatware that bleeds everywhere…no matter how hard I try, I cannot get rid of it all. I’ve already contacted microsoft support, and they said that using the digital river iso’s on oem machines is perfectly fine…as long as the product key on the COA sticker is valid for the windows 7 version on the iso. Thanks so much for putting this together!

    1. Amy ensure you backup the SLP Activation of each install using the ABR program before clean installation see here:
      This will save a lot of hassles with Microsoft Product Activation in particular if the COA is faded. I only have the Dell activation files so this is particularly important if your systems are not Dells.

      Clean installs have always been much faster and efficient in my experience.

      1. I had a windows 7 home premium pre installed on my dell xps l502x laptop.i lost the DVD that came with the purchase and the product key has faded away.after 2 or 3 years i installed windows from “softlay” website because my laptop started to have more virus an started to lag… but it is 30 days trial witout product key.if i follow ur steps , can i get back my original OS

      2. To activate Windows 7 Home Premium using OEM system locked preinstallation follow the instructions here: (4:08 onwards)
        Should you wish to activate Windows 10 Home then create a genuine ticket after this:

    1. Microsoft has a free tool that will help you make the recovery media for either 8 or 8.1………you have to have the product key or you would have had to make a system image prior to this or your machine would haved had to shipped with 8.1 pre installed

    1. Use the Home Premium or Professional 32 Bit version and create a bootable USB.
      Once the bootable USB is made delete the ei.cfg file. The ei.cfg will select the version to install automatically and deleting it gives you a screen presenting you with the option to install Starter. This is explained in more detail above.

  3. Would the pro install be fine for installing on a brand new hard drive on a HP Probook (6560b)

    1. If you are trying to perform downgrade rights then you need installation media with HP system locked preinstallation as no Windows 7 key is provided for downgrade rights. I have these for Dell systems listed here

      For HP I have the files for Home Premium and can probably make these up for Professional and Ultimate from that (I have not uploaded these yet and these are untested).

      If the system has a Windows 7 Professional COA included then you can use the 25 Digit product key on that and manually activate via phone.

  4. I bought a new Dell Windows 7 Professional 64-bit SP1 installation DVD on eBay. The intended recipient PC will not boot to it. I can not open the CD. I have three PC’s running here. They don’t recognize it. What easy step have I missed?

  5. This is an E521. Oddly, it has a Vista sticker but XP OS. Just as when I try to boot to it, when I try to read to it in Explorer, the DVD drive eventually just flashes and everything stops.
    OK now get this. I have a ten year old Compaq Presaro with XP. I push in the disc and it says blah blah your PC isn’t up top specs for this OS. But I can read it in Explorer, see the folders and everything.

    1. Okay so you have a Windows Vista Business COA with downgrade rights to Windows XP. Firstly did you get a new product key with the Reinstallation DVD, if not you should know that the System Locked Preinstallation key from the Windows 7 Reisntallation DVD will be rejected in your system as Dell never sold it with Windows 7.

      The DVD drive in the E521 does it read other DVDs? You can try a lens cleaning CD as there may be some dust blocking the DVD laser. Its also possible that the DVD laser has failed (if it can’t read other DVDs this is likely the case):