No video, doesnt seem to boot.

My video card fried on me a few years ago, then I was given a different video card from a friend as his computer seemed to BSOD with the video card in it. After a few weeks mine started doing the same thing. So my PC sat until I ordered a new video card. Until today in fact.
I'm working with an ASUS A8N-SLI SE motherboard and Athlon 3200 CPU.

The problem is when I installed the new EVGA geforce 650, the fans started up but no video.
I disconnected all the drives and yanked out all my pci peripherals, no changes.
I put the old Radeon back in that my friend gave me, same problem. I took out all the drives and PCI slots, no luck.
Put in a fresh CMOS battery, no changes.
Have used 4 different RAM stick individually and in combinations. nothing.
Thought maybe my 450W PSU wasnt giving it enough juice so I went to the local shop and got a 475W (The biggest he had) no dice.
Took out the motherboard to see if maybe it was a short circuit on the case and or risers, nothing.

I have no clue what is wrong with this blasted thing, does anybody have any idea what the issue might be? It's also missing the internal speaker so I cant tell if it does the POST beep or not (If somebody knows a workaround for that, that'd be a big help too.)

Any input would help, thanks.

 

Thanks DavidGP, I tried booting with the 6 pin both plugged in and not plugged in. As far as the bios go it doesnt even show the bios screen, no signal output at all. I'll try leaving the cmos battery out while I'm at work today and see if that helps.

 

Took the cmos battery out for a good half hour and tried firing it up, no changes.