Possible Motherboard failure?

I have a problem with my computer, and the cause has bounced from either Power Supply issue (Which it isnt) or Motherboard issue. I got bored one day and took an old harddrive from my old computer that I don't use anymore. I wanted to know if It had an old game I used to play because I couldnt find the cd and I wasn't sure if I had installed it on my old computer. So, I unhooked my cdrom because I didnt have space for another harddrive (I have two already and I couldnt fit a third). So I unplugged my CDROM, setthe harddrive in it's place and booted up my computer.

So, I got a "Boot from harddrive failure" message as well as a "CDROM missing (or something to that effect)" message as the computer booted. It logged on regardless and I got to my desktop and opened up the drive to see what I had on it. After realizing it had crap, I highlighed the stuff and deleted it because there was no need to have anything on it anyway. So, I turned myc omputer off - un hooked the drive - put my CDROM back in and then went to turn the computer on. I pressed the power button and it sounded like it was booting up but I get nothing on the monitor (thought it was the vid card, it isnt), and the power button (which turns green when its on) lights up yellow/orange.

I have fiddled around inside and I cannot find a logical reason for why this is happening. My friend suggested that the board may have overheated or something, but when I press the power button the CPU fan does turn on..so I dont know.

If anyone has any thoughts on this issue I'd be very appreciative if you could share them with me.

Thanks in advance.

-Anthony

So, your pc powers on, but doesn't boot up ? Do you get the POST or BIOS messages appearing on screen or nothing at all ??

Re-open the case and make sure that all connections are in properly, that the graphics card and memory sticks are seated properly. Then, disconnect non-essential peripherals and try to boot with minimum specification and see what happens.

Have you tried the graphics card in another machine ? With nothing appearing on screen, that would be my first port of call.

Also, before you started tinkering about inside the case, did you manage to earth yourself correctly ? If not, then it's possible that static electricity from your body has fried a component on the motherboard - but try other options first before condemning the motherboard to the bin !