Macbook Keeps on going into sleep!

Hey guys I just got a used Macbook. It's a Black Macbook from 2007 with a 2.16ghz core 2 duo, 2gb of ram, and a 160gb hdd. Anyway so whenever I turn it on the backlight flickers, then turns off. It proceeds to boot into the OS, and then the backlight turns on. Right after that it goes into sleep mode. I can't use the computer. When I press any button it comes out of the sleep mode but in a few seconds it goes back into sleep mode.

I've tried re-installing the OS from scratch and I've tried resetting the PMU and the PRAM/NVRAM. I also took it apart and disconnected the inverter and reconnected it to see if it would help the backlight problem... it didn't.

It does it both on AC power and Battery.

no one?

I have absolutely no clue. Perhaps there is a problem with your display? I suggest you take it into the Apple store if it's still under warranty.