My PC froze and never booted up. I replaced the power supply and now i can get power to the fans and the hard drive but no POST is happening.
I reset the CMOS by
- disconnect AC
- taking battery out
- clearing jumper
I left this for >5 min and still no POST after reconnection.

I even took memory module and graphics card out and barebones machine - no response to power button switch. I am not sure what the problem is. Please help.

Gary

Had it been working OK up until this happened? Or is this a new build? What make/model/wattage PSU did you install?

All you need to get a display is the CPU w/HSF, video card w/monitor, one stick of RAM, & keyboard. Temporarily disconnect everything else.

Everything is disconnected. It was working fine until it had stopped working and wouldn't boot by pressing switch. I thought it was the PSU which itself was quite old. The new one i got is Orion HP485D 480W PSU. It doesn't seem this is the issue. I checked all connections and it is weird how when i switch the psu on the fans and the HDD come on but for anything else.

I have a CPU HSF and video card connected along with kbd. everything is disconnected. Just to see what happens or i get some beeping i disconnected everything including memory, vid card but no luck.

CMOS should be cleared based on the steps i followed with AC out.

It could still be the PSU. The Orion is a cheap piece of crap. How much did ya pay for it...$20?

http://www.directron.com/hp485d.html

Hmm no man - The first PSU that i thought was busted actually works fine on another machine. So the problem can't be the PSU.
What is a sureshot test to see if the motherboard or the CPU are gone?

Check for swollen or leaking caps on the board. The pics on this site will show you what to look for:

http://www.badcaps.net/

Otherwise, pull the CPU & look for signs of scorching or overheating. If you can, try the CPU in another board.