What is causing the computer to only run 0.5 seconds?

ahthurungnone

Distinguished
Jun 9, 2010
616
0
19,010
When I turn on my computer, it simply powers up for a split second (actually about a half second). Then it turns right off. It will not turn back on.

If I turn off the power supply, and back on, it will do it again.

If I wait twenty minutes, and power it back on. It works fine.

What component is defective?