auto restart problem

Whenever i am using heavy load applications, especially writting cd, copying cd onto my comp. or creating its image, the system restarts with a blue screen for few seconds. The process like copying cd or crating image continues for about 20-50% and then the system restarts. Could it be the hardware problem?
Please help me out.

i got a new pc where my specs is AMD sempron 2600, 512 ram apacer, triplex ati radeon 9550 256MB card....

i couldnt play games like UEFA2005 and underground 2 with this new system..these games work fine with my old system..

i got all updated driver ati catalyst 5.7 , latest motherboard driver..

anyone ,pls help me?i m desperate to solve this.