Random PC shutdowns

[Blues&twos]

Hello, can't give more details at the moment, as the query was from a friend of a friend, but just thought I'd ask... here's the problem

Packard Bell Ixtreme M3720 desktop running W7 switches off unexpectedly with no prior warning. It's been in for repair twice, to quote the owner:

"first time fan cleaned... second time no fault found only seems to happen at home and we've even changed the cable!"

"just shuts down... black screen no warning, no message some times runs half an hour sometimes 2 some times 15 minutes. It's a Packard Bell"

Apparently it's been running this morning for 4 hours with no problem. Not sure what she means by "only seems to happen at home"...maybe the fault doesn't happen when at the repairer's.

Any suggestions gratefully received.

EDIT: may be related to overheating apparently (PSU).

[PhineasC]

Windows XP thus by extension Windows 7, hopefully, has an event log that can be viewed with the event viewer.
Open Event Viewer
Kick the event viewer off and start hunting around. This isn’t spiritually rewarding but can help, I think shut downs due to overheating are logged.

[mad_jock]

I suspect its over heating due to positioning.

All the new processors will just shut down the computer if they over heat. Get a CPU temp monitor to see whats happening.

It won't shut down in the shop because it will be sitting on a bench with good circulation and more than likely air con.

In the house rammed up against a wall with piles of books etc either side of the case is a different situation.

[Blues&twos]

Thanks both, have checked with the owner, and it seems that she has recently bought a new printer which has been positioned so that it partly blocks one of the PC casing vents. I've told her to move it and make sure the PC is properly ventilated, and not near any heat sources (like a radiator, for example).

If this sorts the issue out, I owe you both an equal share of the Mars Bar she has offered me as a reward.