egafd.com

I have tried Speedfan - it also gives the rapidly-changing crazy readings.

I'm downloading Everest Corporate Edition on good old eMule now.

Well, I've installed Everest Corporate Edition and it is showing a fairly constant, sensible CPU temperature.

The help file doesn't give any indication of how to use the system stability test - how long to run it for; how to interpret what it says etc....

No matter what software you use, they all get the temperature value from the same source - the motherboards sensor.

Apply a vacuume cleaner to the fins on the cpu heat sink. a build up of dust on the heat sink can reduce the efectiveness of the heat sink by up to 50%

I would run the stability test for a couple of hours (ideally you want to leave it running overnight) and note what temperatures are like whilst the CPU is at 100% load. Then run just the memory test, then just the hard disc test. If it passes all those without crashing run the lot of them.
Until you tell me what CPU and Heatsink/Motherboard you have I cannot do any more.

Dear Crofter,

the motherboard is a Foxconn 760GXK8MC-RS and the processor is an AMD Athlon 64, 2000 MHz (10 x 200) 3000+.

I don't know what make the heatsink is.

I recently had an Athlon 64 3500+ which ran around 29-36 degrees when idle. I had a decent arctic freezer pro to cool it though.

I do know that those athlons weren't the best when it came to watching dvds, and mine did run pretty hot, so with a stock fan, and less processing power, I can easily imagine yours overheating.

Get yourself an athlon x2, or intel core2 duo.

It looks like you need a new motherboard anyway, so just upgrade the cpu and ram while your at it.

Yes I think these old Athlons can run pretty hot, but as long as the system is stable it isn't a problem, what temps are you getting when you stress your full system??

Well, I've run each of those tests for half an hour and the CPU got no higher than 51C (yes, I know I should run them for longer, but the machine had been shutting down after just 10-12min of video processing)

I'll run them all together tomorrow.

Well if the test runs ok for a couple of hours with decent temps. I would guess that it could be the actual software that is causing the problem of your machine restarting, as converting a video isn't going to stress your PC as much as running these tests.