Built a computer -- powers on, but no video?

[weas]

I recently built a new computer, and while I've built a few computers in the past (3+ years ago), I'm totally stumped as to what the problem with my setup could be.

I'll get started with my specific hardware:

Pentium 4 3Ghz LGA775 530J (Retail)
Epox 915P EP-5EPAJ Motherboard (First try)
Asus P5GD1 Motherboard (Second try)
2x512MB PC3200 RAM
MSI NX6600GT-TD128E PCIe video card (Retail)

My first setup was with the Epox motherboard. After getting the processor seated (with a very thin layer of thermal paste between the processor and heatsink), installing the RAM, video card and hard drive and hooking up the case cables to the motherboard, I tried turning the system on. The motherboard fans and CPU fan all start up, and the case lights turn on, but the post code LED on the motherboard reads 00 and no video is being output to my monitor connected to the video card's VGA port.

After some mucking with it, I decide the processor must be dead so I send it back for a new one, and a new Asus motherboard. Same problem, but no post code since the Asus doesn't have an on-board LED indicator. I tested the RAM in my roommate's computer, and tried an old PCI video card, but I still had the same problem -- turns on, but no video. I don't know if it's a problem with the video card,the motherboard, the processor, or something else.

I'm totally stumped...has anybody seen the likes of this before?

 

[deftech]

Try pulling the video card out and see if the motherboards gives a beep code.

Try pulling the ram out and see if it posts.

Try a new p/s.

Do this one at a time, so you don't pollute your variables.

Best way to troubleshoot this situation is leave everything unplugged from the power supply and the motherboard except video, ram and cpu. Everything else is unplugged, including power connectors. This way you have 4 things to troubleshoot, cpu, video, ram, and power supply.

Unplug each one, and see if it posts.