Vista blacked out repeatedly on me a couple of days ago. The symptoms were: I could log in with my password, but as it was loading everything went blank... nothing, just a black screen. As I restarted it gave me an option to start in Safe Mode. Not knowing anything about it, I decided to try starting in Safe Mode - must be Safe, right?
From there you have the option to Restore, or Restore from last known good working configuration, or Restore from a specific date when it was working well.
After trying all the others with no success, I chose to Restore from a specific date (about 2 weeks ago)and it all started working again.
I have no idea what caused it. There was no virus detected, so I'm thinking it was a Vista hiccup which I assume will be fixed soon. I believe Vista has a self reporting function back to Microsoft.
I have the Vista Premium version, I guess if you have a different version it may not happen to you. Other than that I have not had any problems.
I found Vista to be mostly similar to XP home. My favorite though is still Windows 98, which I learnt on. Sentimental ol' gal.