computer completely locks up randomly

[QueBert]

It's one of those HP touch screen all in one PC's, I looked at the event viewer hoping to see an error from the times it's locked up. He wrote down the exact time from the last 8 times it's done this. I ran Spybot, Superantispyware, Hitman Pro & HIjackthis. I found a few small things but nothing serious. I'm thinking it's a driver but without an error log or BSOD I'm sort of blind here.

Anyone have a suggestion for a program to run that might give me some heads up here? The lock ups aren't occurring from 1 thing. Once it'll be while he's playing Full Tilt, the next will be him on the web.