Video Card Problems

I bought a new mobo an asus a8n32 sli deluxe to upgrade an a8ne board i was using and i also got a amd athlon 64x2 4800+ processor to upgrade and thlon 64 3800+, a lightscribe dvd burner and a 160gb wd sata drive. I replaced the mobo and cpu . Then i started to hook up all my other parts. When i got done hoocking everything up my system would turn on but i would not get anything on my monitor it was just black. i tried reajusting the card i even removed the back plate to see if it might be causing it not to seat right. but nothing. i took it to get it looked at and all the guy did was what i did and he also tried the card in the other pcie slot. but nothing worked. Do any of you know what the problem might be.

He is my system specs.
Asus a8n32 sli deluxe
athlon 64x2 4800+
6800gt XFX pcie video card
2 gigs ocz ddr 400 dual channel in 2x1gig sticks
1dvd burner
1 lightscribe dvd burner
2 160gb sata hdd 1 seagate and one western digital
500 APEVIA ATX with led
2 120 mm fans
1 80mm fan with led.

Hope the guy didn't charge you for such a lack of diagnostics!

Sadly with so much changed it could be almost anything, so down to utter basics.

I don't know exactly what you mean by "the system would turn on".
Do you get any beeps when the machine is switched on? If not, the CPU isn't even running.

If there is no sign of life from the CPU, then it could be the new CPU or the motherboard.

ok by, i am getting the system to turn on and run all but but my video card.the cpu works just fine. my mobo has a light on it telling me when something is not runnin on the system mainly for it showing my cpu and mobo were hooked up right. I hooked my computer up to a second monitor to make sure my monitor did not die. The monitor i hooked it up into has a blinking light if it does not have a video signal going to my monitor and that is what i got a blinking light. the only things that i cannot test is the video card and my mobo. but since the light stays green my mobo it should not have problems. my last thought was may my 500 watt power supp;y cannot handle the load of my system.

also my system does not or did it ever beep when my system comes on. I bought these parts straight from the same guy i got my pc from he tested my mobo and processor with a mideo card in it before getting it to me. So i know the cpu and all works.