I’d been hassled by a subset of Microsoft MVPs for providing this guide however its a corner stone of the Windows Reinstallation Guide and one of the main reasons I designate this guide as “unofficial”.
I have therefore compiled together complete information including download links to Windows Vista and Windows 7 Reinstallation media. This includes the OEM system locked preinstallation activation mechanism found in the Dell Windows Vista Reinstallation DVDs and Dell Windows 7 Reinstallation DVDs. These are now incorporated into the Windows Reinstallation Guide. For full instructions including the download links see:
Windows 7 Player 1: YouTube
Windows 7 Player 2: WordPress
Windows Vista Player 1: YouTube
Windows Vista Player 2: WordPress