Nothing on Screen, Graphic card or Motherboard problem?

Okay, just over a year and half a go (July 2007) I built my third computer.
Intel Q6600 2.4
2GB of RAM 1066
ASUS P5K DELUXE
GeForce 8800 GTS 320
All put in the Antec P182SE Silver Mirror Case with a 650 Watts power
I don’t overclock any of it.

I do a dual boot with Windows XP Pro and Vista Ultimate.
I have never had any real problems with the computer. In Windows XP I installed the Asus Temperature monitor so I can see how hot things are getting. Most time at boot up it would be something around 85-90 Degrees F for both the Motherboard and the processor. (Give or take a couple of degrees)

After playing some game, it would jump to around 105-110 Degrees F for the motherboard. I guess I always knew the motherboard would get hot, but never seemed to get to hot? A couple of times in the last week I was playing the new Call of Duty in Vista, and it would just freeze on me, or end up crashing. I assumed this was my graphic card getting to hot? Nothing that would keep it from not booting up.

Then today I turn the computer on. Powers on fine, but nothing shows on the screen. (The screen turns on, but never gets a signal)
I did test the monitor on another computer and it works fine.
After trying different things, I realize I’m not getting any real post, like I can tell its not booting up (not reading of the hard drive) also I don’t get any lights on my Keyboard.

I first assume its my graphic card. The graphic card does have the fan spin and getting power? I took out the graphic card and put it back in. Or it could be my motherboard.

So before I go off buying a Graphic card? Is there anything else I can do to figure out the problem? ??? What problem am I going to have if I go install an ATI graphic card with out uninstall the Nvida drivers?

Please let me know!!!
Thanks

Thanks,

The link you sent is not working

http://www.tomswiki.com/page/Troub [...] +New+Build

I'm not sure why?

So, last night I realized I wasn't getting any Beep at all. Not even one when it posts.
I took out my graphic card, still no beep.

Took out my ram, unhooked the hard drives and DVD drive. (only the CPU was in)

still no beep. Nothing at all.

I assume this means Motherboard. (I guess it could still be Processor?)

I reset the Cmos and same thing.

I ordered the same motherboard again so I wouldn't have to re-do my whole computer.
I hope I'm on the right track.

I had the same problem. I took my comp in for testing and it turns out that my memory was bad, so it would not POST or show any signal.