Replaced iMac hard drive, now no display!

I recently upgraded the hard drive in my iMac 20" 2.0 core duo following the instructions here. Everything went perfectly. Until I tried to boot back up. Now I have no display. I tore down again to double check my connections but they are all fine. The computer starts up, the light comes on, the hard drive spins, the CD drive spins, but no chime (I had it muted on last shutdown), and no gray screen, just black.

Tried resetting PRAM but no luck, tried booting to Install disk, no luck. HELPPP!!!!