I just hit this same problem, although I've seen it in the past, probably about 5 or 6 months ago. It happened a few times and then I didn't see it again until today? Today it's seemed a lot worse though, I had 3 crashes in about an hour. Like everyone else I also have Avast , but I'd be happy to un-install it install something else. Does anyone know of a good free virus checker similar to Avast that doesn't cause this problem?