PC Auto restarts

[patkim]

I have started noticing occasional automatic restarts (as if Reset button is pressed) After 2 – 3 hours of operation.
I have been observing that my CPU is now getting hotter than what it would be in the past. I am wondering what would be causing it as I have not made any changes in my system H/W or S/W or the processing load/duration etc for past several months, plus this is winter time now.

The hardware utility or BIOS shows around 40 Deg C but I am skeptical about it.
The heat is mildly felt even if I open the cabinet door. This was not the case before.

My config… it’s quite old but has worked well for past 4 years!
AMD Athlon XP 2000, Biostar M7NCG 400, 512 MB, 300 W SMPS, NVidia 6200 AGP card, 80 GB HDD, one DVD RW, XP SP2, one additional fan in the cabinet. All fans CPU, Cabinet + SMPS are operational.
The only change I notice is that CPU fan is now making more noise that before. This is old system and as such there's no facility to control / vary fan speed based on CPU temperature

The auto restart issue is only noticed after 2 – 3 hours of continuous operation. Hence for the time being I am assuming it could be due to CPU or such heating.
Any suggestions would be great.
Thx.

[The Sorcerer]

Most probably the thermal paste on the processor has lost its thermal properties.

[patkim]

where do i get the Thermal paste?

[realdan]

also check the heatsink and see if it is clogged with dust and dirt..also check if the fan is spinning fast enough..you could also try oiling it or get a new one..

[The Sorcerer]

You get thermal paste in any pc shop. They cost as low as 20-30 bucks to good quality thermal paste like artic mx-2 for 300 bucks. Make you put it as little as you can- but not that little. The chips inside the proccy is exposed unlike the ones we get now so follow the instructions here:
http://www.arcticsilver.com/pdf/appi...core_expsd.pdf

[patkim]

Thanks for your help and advice..so I decided to clean my PC today and I could notice unimaginable amount of dust accumulation on the CPU heatsink. Though I have cleaned my PC several times…so far I never touched the heatsink…This time I removed the fan on top of it to clean it from inside and see the attached picture..this is what the heatsink fins were holding in it after 4 years!!

The next pic is after cleaning the fins!!

[The Sorcerer]

Ahh good. Did you check the temps after cleaning the fans. If it improved drastically then you dont need to change thermal paste.

[patkim]

As such the temp is still around 40 Deg C but I guess the heat dissipation should now be relatively better after removing heap of dust from the heatsink.
Will now keep it to test for a few days and see if there are any more restarts.
Thanks