It had been running at first for about half an hour, I think (I wasn't actually there when it started), then it froze when he was writing an e-mail. He rebooted and then it did it again after about 5 minutes. He called me after the second reset, when it wouldn't launch Windows, but can up with the 'boot error', when it said insert system disc and press any key to continue. He powered off, and I went round and started it up, and it started without problem. He started to write his e-mail again (the program loaded fine), but after 2-3 minutes, it froze again. I then opened the case, and pushed the cards and the connectors to make sure everything was seated firmly. We then started it up and ran it with the case open, and it was fine. We ran it for at least 30 minutes, then I put the side of the case back on, and we ran it for another 30 minutes - no problems.
As I said, according to the 'Asus Probe', the CPU temp was about 47C, and the system temp, about 40C, with the case open. With the case closed, both rose by 2 or 3 degrees, but nothing unusual.
Having thought about it, a couple of times before this freezing started, it has stopped for a couple of seconds two or three times before, but then carried on normally. I didn't think this was anything much out of the ordinary, but I'm now wondering if this was a lead up to the current problem? Could this be a dodgy CPU?
I don't think it's connected Sandra, but see your PM.