HELP HELP HELP!

Okay so heres the thing, i was playing guild wars and then a blue screen came on requiring me to restart (no burning smell either and not bsod)
i restart and the bios screen starts to become blotchy and into lines, nothing is readable. It goes to the xp loading screen then the moniter goes to power save mode, but the computer sounds like xp is running in the background. Okay so i figured it was the gfx card or monitor,
1. i try another moniter (doesnt help)
2. i try another gfx card (works longer then the other gfx card)
(my original gfx card was a 6600gt pci-e x16 and my spare was a 5200 pci)
now when ever i start nothing comes on moniter, i dont think its the gfx card, which leads me to believe its the psu or mobo, my doughts are on the mobo because it sounds like windows is running fine in background. but i dno psu sounds fine and everything powers fine.
i really dont know why this is happening, can anyone please help. i need to fix this before my dad finds out. thanks in advance

 

i forgot to post my specs, here they are
Gigabyte GA-K8N-SLI Socket 939 NVIDIA nForce4 SLI ATX AMD Motherboard
AMD 3200
ASPIRE ATX-AS520W BLACK ATX 520W Power Supply
Maxtor DiamondMax 10 6L200M0 200GB 7200 RPM Serial ATA150 Hard Drive
PNY VCG6600GXPB Geforce 6600GT 128MB GDDR3 PCI Express x16 Video Card
CORSAIR ValueSelect 1GB (2 x 512MB) 184-Pin DDR SDRAM DDR 400 (PC 3200) Unbuffered Dual Channel Kit System Memory

 

Well, once when I was getting anything on the monitor it was because i accidentally set the primary display adapter in my pc wrong. There is a little batter (kind of like a watch battery) that is on your mobo that powers the bios. I had to remove that and replace it for about a minute to reset the bios settings. That got my screen back. Not sure if that'll help you out at all. If you know what i'm talking about though, you may as well try.

 

well i dont think its a setting error i think it may be more of a hardware issue but if it doesnt hurt to try ill just try it

 

sounds like your video card was overheating bad and it didnt shut down.usally its shuts the pc down.if it happens again take the side off and blow a house fan at the video card and the ram.bad ram can cause this too.i had both happen to me....hope this helps...peace

 

Have you tried another psu ...

 

nope i dont have another, so im saying what should i buy to fix this,
actually today i tried another moniter with that new gfx card, and it seems to work, so afterall i think it was the gfx card or moniter