Oh, this topic is still up.
It's a very weird thing. I took it to friends who were a little tech-y... nothing. One told me it was a bad mobo, another said there was something wrong with the power getting to it. So I ended up getting a new computer. About nine months later, I try it just on a whim, and it works. Just as it did beforehand. It's been working now for nine months without a hitch... so far.
So, I guess that's the weird thing about vaios. I've read lots of stories where people leave it alone for a while and it suddenly works. This was one of those cases.