Help Please, Output issue

I went to work and left my pc on for my dad, came home and he said it stopped working. There was no output to my pc monitor, we have a spare crap pc show i checked the monitor and no problems (using it now) also checked my graphics card in the other pc and there was a display through it.

I have bought a new motherboard and CPU, and that doesn't seem to help. I am getting more and more annoyed by it all. I have built the pc outside of the case i as had heard that sometimes helps and still no avail.

Any direction welcome as i can't keep throwing money at it

Thanks

Welcome to Dev Shed.

When you turn the computer on, is there no display even during POST? Or is the display not showing during Windows?

it's just no display at all, not even during post. I have bought a POST card but don't have a clue what i'm doing with that.