You've done a pretty good job so far. The next steps would require disassembly.....if the laptop is still under warranty then send it in to Compaq for repair.
If not, all you can hope for is either a cable/connection problem or a failed inverter board. The other two possibilities would cost a lot to fix...motherboard or LCD panel. The inverter board may only be available as part of the LCD assembly.
So, the only thing you can really check for is a bad cable connection from the LCD to the motherboard.
Doug
dxd_2000@yahoo.com