Rebooting PC

StockportGerbil

Folks :-
A friend of mine has a PC that reboots after a period between 5 minutes and a couple of hours and it's bloomin' frustrating for her. I've had a quick look at it and can't see anything wrong with it.

It's fairly recently built, all the components are properly seated, I've stripped it down to video card and hard disc and it's still doing it. It's running Windows XP. There are no clues in the event log. I've cut down the number of processes running from start up with no joy, the BIOS is configured to use the default settings / no overclocking.

Any ideas how I can isolate the problem?

(Just had a more thorough look through the site and one of the FAQs seems to cover this, Memtest86 and checking the heatsink has been put on properly look to be the way to go. In my defence the question is a bit buried. Sorry!)

Thanks

Kev

banger9365

mite be bad ram ,can you try a different stick off ram

Idiophreak

It sounds like some kinda overheating to me - have you tried install sisoft sandra or anything like that to keep an eye on temps?

It's always worth popping the heatsink off, making sure the thermal paste is in the right place then sitting it back on - got to be worth a try.

CHR15

It's worth having a poke about in the BIOS settings if you are comfortable looking around in there.

there is usually a temperature threshold level at which the PC will shut down to protect itself.

The same page will show you the current relevant temperatures.

The default settings are usually very conservative and can be modified (the whole feature can be disabled) but remember it is a safety feature to protect the mainboard components so be careful.

woo

You can get memtest here http://www.memtest.org/ to create a CD to check the RAM.

cdbrown

Could be a number of issues including an iffy power supply (one of the most overlooked important components). Under certain loads - perhaps heavy hdd access, or cd-rom access - the PS won't be able to supply the required voltage on a particular rail which can then lead to rebooting.

Memtest is an easy way to see if you have any bad ram - I would only test it with 1 ram stick in at a time. It's designed to show a fault and not just randomly reboot - if you get reboots during the memtest then it's most likely something else (hint power supply).

Good luck.

Idiophreak

Also, try and be sure that nothing else is changing and causing it to reboot...I thought mine was doing it randomly once, but after a couple of months I noticed that it was made worse when I knocked the case - turned out to be the mb shorting on the case....

StockportGerbil

Folks :-
Thanks for the thoughts.

Since taking the PC home I've had a closer look at it. I knew it was built on the cheap (my fingers being cut on the sharp edges of the case go to show it's at the cheaper and nastier end of the spectrum.) So the PSU may be a problem, however ...

Given the comments above about the CPU heatsink I took that off and the heatsink compound had turned rubbery - is that normal?

I removed it and replaced it with some stuff I bought from Maplins. I ran memtest overnight and that's shown some failures after a few hours. So I guess it's the memory. Fortunately my friends still got the receipt so it's a trip to Microdirect to hopefully get some replacement memory.

Thanks for the help

Kevin

StockportGerbil

Folks :-
In case anyone is in the slightest bit interested I had a lightbulb moment yesterday and seem to have fixed the problem.

Like I said the PC was built on the cheap. The memory consists of 2 sticks of 512Mb memory which appear to be the same. The fail memtest after a few passes. Since my last post I tried them individually and they work fine.

The motherboard had been set up to use them as a dual channel pair, I've disabled that and (touch wood) everything seems to be working fine now (at least it's survived an overnight run and I left it playing a motley assortment of AVI files this morning - any other ideas of how I can stress test it?)

Once I get my hands on the receipt I'll know if the memory was sold as a matched pair (in which case I can whinge at Microdirect) or not (in which case I can whinge at the bloke who built it.)

Thanks again

Kevin