I have a PC with the following configuration;
Processor P4(2.4 GHz), 384MB(256+128)ram, Asrock Motherboard, DVD writer, 40GB HD, Windows XP Media Center installed.

The problem is whenever I do some software installation computer reboot by itself suddenly. The same is observed when I do the use of CD/DVD drive; either CD/DVD-Writing or installation of a software from DVD Drive. But things go smoothly when internet browsing or any low resource consumption works. I reinstalled the OS several times with full format so no virus threat also checked the cpu temperature and it is always less than 50C, seems like SMPS has gone weak. Somebody please figure out the glitch.....thanks!