i am having this problem .As in the CMOS Setup under H/W monitor my smart fan target is 50 degee / 122 . when the cpu temperature reach around 85 degree my com auto shut down .Could it be the cpu fan problem?As it seem to be unable to cool the cpu down.

Could be a fan problem. Are you familiar with working inside the computer?

Open it up and watch the fan. Perhaps clean the fan. Perhaps remove the fan/heatsink and clean/change the Thermal Compound. Perhaps get a new cooler (heatsink/fan).

Is this a new problem?

Does the CPU always go up to 85c/shutdown? Or only during certain procedures?

ya i cleaned the fan n heatsink just happened last nite normally is around 50 degree.i observe the temp from H/W when i start the com it would be around 60 degree and the temp will constanly increase to around 85 degree and the com will auto shut down.

There are a lot of variables but most CPU's will run at 40c or less under no load. 60c would be a max load.

Is this a new problem? Did it just start to happen? Is it an old CPU?

Have you removed the heatsink/fan and changed the thermal compound?

ya this is a new problem. IT just happen yesterday. nope just fix the com last year.I don't have extra thermal compound to change now.

If you cannot even start the computer I would suggest first cleaning/changing the thermal compound.

Another thing to try is remove all hardware save the CPU / RAM / Graphics Card and see if that changes anything.

The PSU could be another suspect but I would start diagnosing via the steps above.

i done all that ..chaging PSU remove RAM and graphical card.I have not try removing the CPU . k i go get the thermal compound later .

Also examine the motherboard for any leaking capacitors.

They would appear as corrosion and or possibly burns.

okay i go n check it now..

no problem with the motherboard. i go get and change the thermal compound tomorrow.