PC won't display anything

[impakt]

I'm trying to fix a PC for a relative. She told me that one day the PC suddenly wouldn't display anything to the monitor. It turns on and everything, it just doesn't display on the LCD.

- I tested the monitor on another PC, and it works fine.
- Tested different monitors on the PC and none of them display anything.
- Then I figured it was the graphics card. Tried graphics card in another PC and it worked fine.
- I tried different graphics cards in the problem PC and none of them displayed anything, even though they work correctly in their own systems.
- I thought then that it was the motherboard, maybe something wrong with the AGP slot. Ordered a new mobo, installed it, and still having the same problem.
- I have tried multiple monitors, multiple graphics cards with the new motherboard and nothing will work.
- I also tried the hard drive in another PC and it works fine.

Does anyone know what the problem is or any suggestions as to what to try next? I haven't tested the memory yet, could that be the problem? I would have tested it but the memory in my own system is incompatible and I don't want to go buy a new stick unless someone believes that may be the problem. Thanks for any help.

 

[dfuze]

If you are using mulitple ram sticks, I would take them out and put one in and test it; then continue testing one at a time to see if anything changes. You can also download and make a booting cd of memtest to see if any errors pop up.

Have you tested the power supply at all? If it is failing, it might not be giving enough power to all the components.