Madcatz

so did unhooking things make it seem like it was going to work but no video? from what you said, thats what it sounds like, that it starting doing more than what it was to begin with.

it really sounds like its the mobo, no video still and no beeps with no memory, but it gives a single beep when the memory is in? interesting, but it may not beep with no memory, rare but some mobos are like that /shrug

but I'd agree with you, trying another video card/memory would be my next step, but try it with another PSU hooked up, one that you know works, just to eliminate the possibility of multiple hardware failures.