Dell Optiplex 390 Desktop PC

[Carl E]

Hello,
This forum was so helpful in fixing a 2231 O'scope, I thought I'd try the forum again. My Dell Desktop died.  It starts up for about 2 seconds and then turns off. I have to push the start button several times before it wakes up. I've replaced the Cmos battery and that didn't fix it. I'm ready to buy a new supply but I'm hoping someone may have a suggestion of anything else to check before I lay out some cash.
Any help is appreciated.
Carl

[up8051]

Probably dried capacitors in the power supply.
I had similar symptoms in the Dell Optiplex 755, five capacitors replaced and PC works agin.

[Carl E]

SOLVED,
  Well it looks like this is a glitch in the ""I didnt ask for this software update that you just rammed down my throat'.  After removing the power cord for 30 minutes, it booted like normal.  I did check all the voltages on the power connector and they were in spec.
Bad Microsoft !!

Thank you all for the reply.
Carl