Hello

Can someone help me?

I have a machine for several years now and until recently it has been working like a dream, but until last week it will not start?

The fans will not start but there is power to the motherboad as the motherboard light is on
I have a Intel d875pbz

The steps I have taken so far are:

1) Changed the power supply and tried starting it and all the fans started running but my screen still says no signal and the machine does not bootup. The hard drives don't boot nor anything else. The only way I could turn the fans off it by pulling the power out of the power supply.

2) I unplaugged everything and just left the CPU and VGA and still nothing

3) I took the new power supply and returned it and got a new motherboard tried it and it doesn't start with the old power supply.

4) I have even changed the VGA card just in case

Any ideas what else I can do or need to do?

Probably should have kept the new power supply to try with the new motherboard. If the old power supply had an issue, the old motherboard potentially could have been damaged as well. If the fans, particularly any case fan plugged directly into the power supply and not the motherboard, didn't turn, the old power supply was probably bad.

If all the components can be independently verified either in another system or by replacement, the only components remaining are memory modules or the CPU. Did you reapply any necessary thermal paste when you swapped the CPU to the new motherboard? Depending on the processor, one can burn up in seconds if not installed properly. Also, is the new motherboard correct for the old processor and memory?