I got a laptop from a friend recently. Its an HP pavilion dv6500. They tripped over a USB cord and it fell on the ground and wouldn't turn on. They then took it to a local repair shop who told them they needed a new mobo. They put the new mobo in and still had the same problem. When you push the power button all the lights along the dash come on, and the fan and cdrom start up but no beeps and then it just like stalls out. the screen stays black, no ext video nothing, but the lights stay on. I have tested most of the components and all work, everything leads to the motherboard but that was replaced. any advice is greatly appreciated.