Memory, Vid Card, Mobo? Boot problem

[daftpunkit]

So I come home the other day to boot my new pc and it turns on just fine except there is not video output. The monitor just stays in the sleep mode. I test it on the old pc and it works just fine, like normal. The new pc doesn't make any beeps or sounds, just all the fans turn on and the LEDs and the vid card and the TR Extreme heatsink etc. So power seems to be fine. I am thinking its maybe the memory, vid card, or maybe the mobo.

So now its the new pc. I ran 12 hours of Orthos and 8 hours of Prime95. It passed with flying colors. I did NOT run memtest86 because I just plain forgot. All I installed was Supreme Commander and Mark of Chaos on a Win XP system.
Stats:

Intel C2D E6420
2GB OCZ PC8500
Gigabyte P965 DS3 Rev 3.3
Sapphire X1950 Pro 512MB
Corsair HX620 PSU

My guess is aimed most likely at the memory or vid card, more the latter. I am not sure how to test it since I don't have any spare DDR2 ram kicking around. Does this sound like mostly a memory problem over the vid card or mobo? The only thing to think it maybe mobo was the no beeps, but that can be the ram too. I am pretty sure if the mobo wasn't acting right, it wouldnt even turn on. The vid card maybe it because obviously the screen doesnt turn on. Which do you guys think it is?

Thanks for the input in advance.

 

[JimiP]

I believe the standard memory speed on the DS3 is DDR2-800, (PC-6400). Perhaps you need to overclock your board to get it to run correctly. Also, try taking one DIMM out and leaving one in. Re-seat the one and see if it works. If not, try the other DIMM. If neither work, and your board is compatible then yes, you have two lifeless sticks.

Hope this helps.