After EddieS reinstalled Windows onto his 14-month-old PC, he found all of his old files in a folder called C:\Windows.old. He asked the Windows forum if he can delete it.
The Windows.old folder gives you an extra layer of protection when you reinstall Windows. When you do a clean install off a retail Windows 7 DVD, the installation protects your files by putting them into that folder. So do many of the restoration tools that come with PCs. Before they restore your hard drive to its factory condition, they move your files to C:\Windows.old and leave that folder alone.
And personally, I consider that a big improvement over recovery tools that destroy your data.
So what do you do with Windows.old afterwards? Once you've set up all the user accounts, you should move your library folders (Documents, Photos, Music, and so on) from C:\Windows.old\Users to their equivalent folders in C:\Users. That way, Windows knows where to look for these files.
After that, keep the Windows.old folder around for a couple of months. Why? Because you might discover that you need a file or two from it. After all, it also contains browser shortcuts, the Windows Mail inbox, and your updated drivers.
Once you're satisfied that you don't need it anymore, you can delete it. Or, if you're sufficiently cautious, you can copy it to an external hard drive or burn it to DVDs, just in case.
Read the original forum discussion.
Contributing Editor Lincoln Spector writes about technology and cinema. Email your tech questions to him at email@example.com, or post them to a community of helpful folks on the PCW Answer Line forum. Follow Lincoln on Twitter.