GUYS!!! THIS IS COOL!!!
I finally able to damage by PC....its undetectable, software only, and works in only one month....
This is how...
Create a simple program loop to calculate 50000! (factorial) again and again while you lock your computer. never turn off you PC... just lock it. Because the processor never rest....it damage the capasitor of its northside bridge (the cap is bloated)....and your PC become unstable. WOW!!! Haha, now I have a new PC....well, at least its faster than before.