Computer doesnt turn on

[ramteja]

Hello,
my hp pavillion desktop 6720f, has a wierd problem.

Powersupply turns off immediately when I press the start button.

If I remove the PSU521 cable from the powersupply.. all the fans run.. but the computer doesnt turn on..

with psu521 cable in, no fans turn on..

Can some one help me .

 

[socialfox]

What exactly is this PSU521 cable? It would be best if you can describe how the cable looks. In addition, people I have met with a similar problem have found their motherboard to be at fault.

Edit: Also give this a intensive/thorough read
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems