Omega pc problem (wont even startup)

Hey,
My P.C broke a few days ago, basically i smelt burning in my study comming from the power unit and my pc was off. I tried to turn it back on and it wouldn't so i bought a new power unit off ebay. My pc does turn on however nothing shows up on the moniter. I opened it up and turned it on and the fan for the processor is working, the cd-drive is working, i tested the graphics card and it works on my other pc. Could it be the motherboard? An orange light at the bottom right of the motherboard comes on when i power up my pc. Please can someone help:biggrin:

I could post pictures if that would help

Jam it back in, in the dark.

urrm i don't have a manual for my motherboard:ashamed: It doesn't make any beeping noices either. If the processors fan is spinning does that mean the processor is working?

There's nowhere I can't reach.