Use what?
If you're talking about the GT card.
I don't think temperature is an issue, cause when I play The
Sims 2.
My computer doesn't crash at all, only Natural-Selection and GTA
series.
But with the GTX, I can play Natural-Selection fine.
Testing GTA San Andreas now.. already 18 mins still not
crashed.
Update : My dad tested my 8800GT on his computer, it get black
screen.
So it's confirmed that problem is the card. I'm going to send
the card to repair.
Thanks everyone for your help.
Don't need to post here anymore as I found out the problem.