PC Problem

While I am playing metin for 5-20 mins , exactly when i am lvling , my pc have an autorestart , idk if it's when a problem with my pc or it happeneds when i play metin , so pllllz help me ............ :'( , btw this problem really sucks , becoz i got to relog again into ch 11 that's full most of the time , and i lose the zealotry "heat" when this happeneds -___- , help me