So it started 2 days ago. I was playing with my sisters old computer so i decided to steal her harddrive and put it in my computer. Soon after installing it my computer starts to crash. At this point i had 3 hard drives, 2 CD-ROM drives, a 6800GT gfx card, a PCI sound blaster x-fi card, and a PCIwireless card in the comp. The moniter would screw up and go all blank, I would have to hold the power button and wait for it to turn off. I did this twice and after the third time it wouldn't boot. So now when i turn it on, the moniter doesnt turn on but the computer turns on. The mobo turns on, i can see all the lights on, the cpu fan starts to spin, then it spots, then it starts to spin again and repeats this process for a couple seconds then the cpu fan spins like normal. Im not postive if the hardrive powers up but im pretty sure i felt/heard the disk spinning inside. So im thinking its the power supply that fried on me. I go out and grab my sisters old comp and grab the PSU to test it. The same thing happens. So now im thinking its the gfx card. So i take out my AGP card and put in one of my dads old PCI ATI cards. Same thing, the computer turns on but nothing comes on the screen. I tried each one of these tests with 2 different moniters and the same thing happened every time. Sometimes if i left it on long enough (as in atleast 3 to 5 mins) the moniter starts to turn off and on by itself saying power off in 5 seconds and if turned on manually it would say check signal. So now im just trying anything, i took out the ram and switched them, tried all types of combos with my dual 512 RAM to no avil. Also, durning these tests, the light on the PCI wireless card turns on, the lights on the case turn on, the CR-ROM drive light blinks green or stays green like its working, the fan on the gfx card turns on and spins. So know i think its the mobo but i dont want to go out/order a new mobo and turn out that that isnt the problem.
Help please, i usually can do everything by myself but this time im stumped. I built this comp about 2 years ago and have never had a problem with it. My specs are:
nVIDIA GeForce 6800 GT
GIGABYTE "GA-K8NSNXP-939" nForce3 Ultra Chipset
Aspire 520W 12V Black Triple Fan Aluminum Power Supply
AMD Athlon 64 3500+
Corsair Value Select 184 Pin 512MB DDR (512MB x 2 = 1GB)
Edit: Also there are no beeps at all. Acts as if it were just booting up like normal. I tried resetting the cmos/bios by taking out the battery but i couldnt quite get it out and didnt want to get to physical and risk breaking it or something so i just left it there.