Install any version of Windows using any Windows disc you can find
Reader Chris needs to reinstall Windows 7 Home Basic on his laptop. Just one problem: he lost his recovery discs.
A more common problem is when you need to reinstall Windows and you never had recovery discs to begin with. Few manufacturers provide them anymore, and many new PCs don't have optical drives even if they did.
Thankfully, there's a way around this. All you need is a Windows ISO file (basically the entire Windows operating system in a single container) and the free Ei.cfg Removal Utility. The latter deletes a key file inside the former, thus allowing you to install any version of Windows.
Let me explain that a bit further. Windows 7 and 8 installation discs are version-specific; they're designed to match up with your product key. That's why you can't use, say, a Windows 7 Home Premium product key to install Windows 7 Professional, even if you have a disc for the latter.
Likewise, even if Chris somehow laid hands on a Windows 7 Home Premium disc, his Home Basic license key wouldn't work. That's where Ei.cfg Removal Utility comes in: It effectively creates a "universal" Windows ISO, one that will install whatever version matches your product key.
From a high-level perspective, the process would work like this: Borrow a friend's install DVD, copy the ISO file from it to your hard drive, then run Ei.cfg. When it's done doing its thing, use the Windows 7 USB/DVD Download Tool to put that tweaked ISO on a flash drive.
Now, just boot from that flash drive and choose the version of Windows you want to install. Enter your license key and you're good to go. (Don't bother trying to sneak an upgrade; remember, your key will work only with the version of Windows that came with your PC. In Chris' case, that's Windows 7 Home Basic.)
Can't find an install disc or don't have an optical drive?
There are "official" Windows 7 SP1 ISO downloads available from the Windows 7 Forums. Update: Digital River links, the long-time source for Windows 7 ISOs, no longer work. Visit Microsoft's Software Recovery Center for official Windows 7 ISO downloads, or Microsoft's installation media page for Windows 8.1.
Contributing Editor Rick Broida writes about business and consumer technology. Ask for help with your PC hassles at email@example.com. Sign up to have the Hassle-Free PC newsletter e-mailed to you each week.