This may be incredibly simple, but make sure your card is pushed in the whole way. So you say the computer doesn't post (power on self test) aka the beep? I hope nothing is fried!! At this point, if the card is seated properly and still no post... have it looked at =) Good luck!
Oh, btw the way that antec psu is nice. I have a antec
True480 . Its a nice supply, quite and plenty of power. SATA + A64 + Raid + overclock = powerhungry!
