I just finished installing all my hardware on a new system. However, when I plugged in the power cable and go to boot it up, it comes on for a quick 2-3 seconds. Doesn't Post, just fans and LEDs come on for a short time.
I thought it might be the video card, so I changed it out for an older one that works fine in other systems. It boots up fine, except for no post yet again. And the screen doesn't show anything.
Processor - AMD Athlon 64 X2 5600 Brisbane 2.9GHz
Video Card - PNY Nvidia 9800 gt 512mb
Motherboard - GIGABYTE GA-MA790X-UD4P
Power Supply - Thermaltake TR2 RX Series 450W
Did you read the section in your motherboard manual about the placement of RAM? It sounds to me like your RAM is acting up. If you have a tri chan kit or dual channel kit there is a special way to place the ram, usually the colored slots on the mobo, not the ones closest to the cpu.