Bud from Nicholasville KY writes:
If I backup only the Windows folder on my PC and then restore it, will I have a working PC?
Backing up your Windows folder, (usually in c:\windows) is not enough to restore your computer should the PC’s hard drive have mechanical problems. The best way to restore a computer back to a previous state is to use backup software that supports disk imaging.
Disk Imaging software will make an exact duplicate of all of the information, files and settings needed to start and run your computer (along with all of your files), then package them into a single file to place on a backup drive. Windows 7 includes the ability to make image files natively, but I recommend Laplink Disk Image  as it supports some advanced functions, like mounting images (so you can restore individual files), hardware independent restore, and comes with a bootable CD to let you restore the image file without having to reinstall windows first.
If you don’t want to backup your PC using an imaging program, the best bet is to just backup your personal files – and should your PC crash, to reinstall all the applications from the CDs or redownload them. Your personal files are usually located in c:\users\yourname (in Windows Vista/7) and in c:\documents and settings\yourname, but there can be other personal files stored in program folders and inside of programs configuration files. This is why imaging programs are so good to use. I highly recommend purchasing one.