Sorry to hear about your loss but.
PC,s as well as MAC's can fail even if brand new, being a MAC isn't garantee that it won't fail.
Windows Update doesn't have anything to do with your PC going up in flames.
Windows Vista sucks hairy arse, I'll give you that
THe moral of the story is BACK-UP your data, or you'll be sorry, be it windows or mac.
When you least expect it it will fail.
Sick 'em Hoff!!!