No monitor signal, no POST beep

[Cerzi]

Hi all

I've just reassembled some old computer parts into a new case for someone, and initially everything was working fine. A day later, however, and the PC wouldn't turn on properly - it'd power up, and after a few seconds of fans whirring, turn straight off. Turns out the PSU was dead (which I was expecting to happen, although it's quite a coincidence it dies then considering I've been using it for the last year), so I put a different PSU. Now the PC doesn't shut off, but nothing happens besides fans whirring. No monitor signal, no POST beep, and no lights on keyboard/mouse (eg caps lock on lights).

Considering the PC, including PSU, was working perfectly fine days before, and the faulty PSU was replaced with one that definitely works, does anyone have any ideas? My guess is that when the PSU died it took another component with it; what is the best way to verify this?

Anyone have any ideas? Maybe I should whip out the multimeter and start probing the mobo?

 

[Davey_Pitch]

My guess would be the motherboard to be honest. If you've put in a known power supply and it's not booting at all, nor giving you any error beeps, that strongly suggests the motherboard to me. If you have a spare floating around you could try that instead of your current one, see if that works. If you don't, then you could try disconnecting everything except the CPU. If it boots you'll obviously get warning beeps as you won't have any ram in place, but at least you'll know the mobo at least boots. Start adding bits back in one part at a time to see if/where it fails.