I would always advise using something which is not dependent on your Windows operating system working. I use Acronis True Image, which has to initially be installed under Windows, but once that is done, you create a Rescue CD which can operate by booting up before Windows loads. The programme makes "Mirror" copies of your hard drive, which can be stored on a separate partition or burned to CD/DVD and kept safe.
When your computer goes belly up, you just restore an earlier working backup image.
Quack!
GtD.