System hangs on long run

[nm_ranga]

Hi,
Mine is Intel 845GVSR chipset motherboard. I have been using this for past 9 months WITHOUT a single problem running on XP. recently my system is getting hung unusually. i thought of few problems and did as follows
1. checked my hard disk with seatools - Found OK
2. checked my RAM with memtest86 - Found OK
3. Formatted my H/D completely and reinstaled XP as well as Win98
4. Dismantled every part of my computer, cleaned it and again re-installed

B'fore i did this things my sytem was getting hung frequently. AFter this it gets hang after a long time (2-4hrs).


P.S .
1. One time the system hung EVEN in BIOS while i was changing settings.
2. Another time systemn hung at OS selection Menu.
3. Another time system automatically restarted and BIOS message displayed like
"System failed last time due to thermal event (Overheating)"

But my CPU processor fan is working well. Also i applied new heat sink compund on the bed. but nothing worked.

I dont know wat is the problem. I tried all that i could do. Pls help me on this
Thanks & Regards
Ranga

[pip22]

Cooling fan on the CPU is sometimes not enough. Additional case fans (one at the front pulling air in and one at back blowing it out) are often required to keep temperatures down. Try running the system with both system box sides removed just for testing purposes. If it runs all day without crashing then it's obviously getting too hot inside the case when the sides are in place. You'll need to fit some case fans. If you've overclocked the CPU then you may have overdone it, so you'll need to 'wind it back' towards it's stock rated speed until it stops crashing.