Computer shuts down just after start-up has completed
Computer goes through it's diagnostics, Dell splash screen, and finally the complete desktop appears. After 15 seconds, the computer shuts down. The power is still on as I can open and close the dvd tray. After waiting approx. 30 minutes, I am able to start the computer and the same thing happens. I have tried replacing the main power supply and the main fan circulation air over the CPU. Any ideas or suggestions?