PC wont turn on

[jonoh89]

I have an old Packhard Dell PC that i have decided to use as a Media Center PC. The PC was in a working state with an old graphics card, however , the power supply was extremely loud .

To solve this issue i bought a new power supply and graphics card with the appropriate connectors.

The system booted up fine and worked for about 10 minutes then it appeared that the screen resolution changed( i may be wrong) and the PC just turned off completely.

The system now wont turn on. I can press the power button and the light will flash for less than a second, the CPU fan tries to spin then instantly everything turns off and it tries to boot again as if in a loop of trying to boot and failing somewhere. The fail is near instant.

I have tried taking out the graphics card and using the old power supply and all peripherals with no luck

Thanks for any advice,

Jonathan

 

[008Rohit]

Short with the case?

take the motherboard out, place on a breadboard and try to turn it on by shorting power pins.

 

[tsnor]

"light will flash for less than a second, the CPU fan tries to spin then instantly everything turns off and it tries to boot again as if in a loop of trying to boot " I agree with 008Rohit above that this could be a 'short, reset, short, ..' loop. The suggestion to pull the pieces is so you can find where a wire is frayed and shorting against the case, etc.

I'd start by pulling the video card and seeing if the PC gives you the beep code for 'no video' or if it stays in the funny loop. (google 'beep code' if the term is not familiar)

Suggest you post the wattage and brand of old PSU and wattage and brand of new PSU.

Here is a good reference for hw diagnostics: http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems