Windows 7 lost desktop folder

You may have a corrupted user account. You can create a new one by going to Control Panel, but be warned that you will need to locate your old one (C:\Users\(Your old account)\Desktop) and move things over that you want on your new one. You won't be able to name them the same either unless you get what you want from the other account and then delete it, but it usually isn't worth the effort.