If his browser keeps shutting down, he may have problems accessing and downloading HijackThis!, but I hope he can. And that's always a good suggestion, Lobos.
I had that to happen a couple of times because of my pop-up stopper and my Ad-Watch Monitoring. I had to turn them off and then start them back up.
Have you installed anything recently?
Let us know if you get HijackThis! and post your log.
Dave