My preferred methods and this is not for everyone, is a complete reformat. I have an external hard drive, 250 GBs where I keep backups of things I really want to keep, plus the usual zip drive and CD and DVDs backups, so I don't mind reformatting, although it can be a real headach to reload all programs.
I have Norton Ghost where I attempted a ghost back-up and the re-install failed. I guess I did not do it correctly but it scared me from using that method ever again.
I like the restore function, you just have to go back far enough and conscientiously create theses points yourself.