Yep I am using windows vista and basically it goes like the following: I launch Skyrim, everything goes well, then 1-5 minutes into the game I hear some buggy sound like scratching sound then the computer freeze and I have to restart. Does this sounds familiar?
Try downsampling your sound on your soundcard, if it's higher 44100 I think then it can get crashy. There is a thread about it somewhere, I had to do it, myself.