Windows XP End of Support
Windows XP reached End of Support in April 2014. I do not recommend Reinstallation of this Legacy Operating System unless its required for specialist applications. I certainly do not recommend using it on the internet.
Windows XP Reinstallation Media
There may be some other cases where you need to get Windows XP running on an old Dell system. Most systems are shipped with a Windows XP Reinstallation CD/DVD. These CDs can usually be found on eBay
Unofficial Service Pack 4
You should also download the Unofficial Windows XP SP4 and save it to the USB:
You can now clean install Windows XP. After installation install the Unofficial XP SP4 and then the system drivers.
You may also need the Microsoft .Net Framework 4.0:
Security for Windows XP
XP should be regarded as insecure even with third party security software installed.
For an Operating System that has reached End of Life you are limited when it comes to Security however you can use Malwarebytes' AntiMalware Legacy:
The latest definitions or rules are available here, you'll to download them on your Host PC and drag and drop the files over to your VM: