to all sifu

my pc been auto shut-down and auto restart all the time whenever i try to play..sumtime jz 5 min into the game and then my pc restart or shutdown..

the situation :
lcd blank but still can hear the background sound
sumtime auto restart
sumtime auto shutdown i nid to re-on the pc myself

im using:
window 7 pirated
gtx460
i7 930
20" lcd

note:
it only happen when i play sc2,other game no problem

game setting:
1600 x 900
i tried ultra,high,custom oso same problem

sifu plz tolong me

no it jz randomly restart , reboot, lcd blank..no actuall time

sumtime when i was playing half way,chatting half way or in afk mode then it will randomly restart

sumtime it took like 5min sumtime more than an hour when it happen..

jz now i tried reinstall but same thing happen

i try out the msi afterburner..my GC heat is always at 60+ whenever im playing sc2..how much is normal?

i cant play league coz sked of dc T__T

been 2 months le,it will shutdown by itself and then i turn it on and play again..i sked 1 day it will come to the point where my pc mati..omg sei lo

dang,,i'll change the ram 1st and see it will happen again or not

owh btw when my comp shut down my mobo kip beeping for about 5 sec..and then i nid to press the on button manually T__T

last but not least a huge thx for all those who replied tq tq tq tq tq tq