Having just gone through three weeks of crap with Windows Vista, I thought I'd share my experience in case someone has a similar problem.
First, let's accept that Vista is the new ME. I'm hoping for better things with Windows 7 (but no, not holding my breath). If Adobe ever writes their software for Linux/Unix, I suspect a lot of folks besides me will stop using MS for our OS.
Three weeks or so ago, Vista suddenly started to randomly blue-screen on me. I hadn't installed any new software or hardware for the previous two months, so you wouldn't think that would be the problem. I could boot into Safemode with networking with no issues. I ran the usual programs - CrapCleaner, HijackThis, SmitFraudFix, VundoFix, ComboFix - all to no avail. No viruses, no malware, nothing evident. I have a Windows Vista repair disc, which also solved nothing.
I really, really didn't want to go through a reinstall of Vista. I would have opted for RC1 of Windows 7 first. However, I decided that maybe the issue was something to do with my profile. I created a new profile, copied anything over that I wanted from the screwy profile to the new one (which has taken the better part of six hours), and then deleted the bad profile.
So far, so good. No problems booting, no crashes (I hope I am not jinxing myself here), everything seems to be working.
It pays to do regular backups, which I do, but moving profile info from one account to another takes a bit more tweaking. Nothing major, mind you, just time.
Bottom line is, if you must use Windows, and have Vista, and haven't had any major problems yet ... do yourself a favor and back up anything you value, like your Bookmarks, email profiles, any sounds/fonts/photos/etc., and you will be ready if/when this happens to you.