I bought a PC (D915GV, P4,512MB RAM with combo drive, no external graphics card) and it is working fine for over 1 and half year and all of a sudden while i was playing NFSMW (two profiles completed) my system got crashed. So after i restarted my PC an error occcured "Your PC was last shutdown due to over heating".This is the first time such an problem(also the first problem) occured. And after that my system never booted properly.And moreover after waiting for it to cool for sometime and when i restarted it boots for a while and again restarts itself automatically for quite some time until i shut it down. I want to know what could be the problem. Do i need to repair the cooling system of my PC.