I have had an HP Notebook xh156 for 3 years, so now out of warranty. Some time ago whilst playing a game, the screen blacked out and nothing I did would bring it back up save for rebooting (by holding in the on/off switch, this was the only way). I thought it was the game that caused it, so deleted it, but the problem kept re-occuring at random times, the more I rebooted, the quicker it shut down, so I thought it was maybe overheating. I didn't touch it for 4 weeks and then for a few weeks after there was no problem, but then it started happening again. It's always plugged in to the mains, so I don't think it's the battery. I've checked all the power settings, they're set to 'always on'. I've also restored the laptop to it's factory settings, but no joy. HP support gave me no answers. Perhaps somebody here can give me a few pointers, 'cos otherwise it's just a very expensive ornament!

My guess is a bad battery, for what that's worth.

All I can think of is display going bad or overheating.

Try to boot into safe mode and see what happens. If it still happens in safe mode, it is almost sure to be a hardware problem.

Which Windows version? .. and have you considered a clean reinstallation (even though this looks most likely to be a hardware problem)?

Is Windows managing your virtual memory and how much RAM is installed and have you considered testing your RAM?

Have you tried attaching to an external monitor (to take the screen itself out of the equation) to see if the same problem arises?

Agree that heat must be on the cards as a cause.

Thanks for all your responses. I've sent it to a poorly clinic cos whatever it is that's wrong is WAYYYY beyond my 'ken'. Thanks again for trying to help me fix the POS.

:D