New
#11
Although I'm going to get a lot of criticism for this one...but I was able to upgrade from XP to Vista to Win7 without fail. For me it was a matter of having a very old software program running that I wasn't able to re-install as the company is gone and it came originally on 3.5" floppies!
I left XP years ago when Vista was in beta. Sure it had snags but I never experienced the horror stories that others have told. I honestly believe that the worst OS MS ever made was ME. That was a total mistake.