Replaced Power Supply, Getting a Black Screen On Startup

I have an early 2006, 20' iMac. A few days ago it was completely unresponsive when I tried to start it up.

I ordered a new power supply and replaced it today.

With the new power supply it started up immediately. However, right as you hear the chime the screen quickly flashes grey and then goes black.

The computer continues to boot however, and I know that it's running....after clicking around the black screen for a while I was able to find iTunes and start it playing music.

I tried multiple SMC and PRAM resets, and when that didn't work I opened it back up and reseated all of the LCD connections.

None of that worked though.

What's very odd is I pressed the power button to put it to sleep, and then when I wake it up, my desktop flashes across the screen for maybe a second or two.

So that must mean there is some kind of connection, and the LCD can't be completely shot, right?

Are there any other options I can try to get it working?

EDIT: Also want to mention it's not the backlight, when I say the screen is black I mean as if the computer were on standby or shut down.