I have an HP dv9000 and the graphics chip went out so I ordered a new motherboard from eBay. I installed it today and while the computer was still apart I turned on the power and everything booted up fine. I turned it off then I turned it back on and it was still working. I continued to put the laptop back together, but when I tried to turn it on again nothing happened. I had no fan noise, no lights at all. I put in the battery and plugged it up to see if it would charge, but all I got was the battery light on the front of the laptop would flash and I would have to press the power button multiple times to get that. Here are a list of things that I think might be wrong.
1.) Dead CPU? Is there anyway to test this? What are signs of a dead CPU?
2.) The power button board. I don't know why or how this would have broken.
3.) The ribbon that connects the power button board to the motherboard. I tried another ribbon and still nothing so I am thinking this isn't the problem.
4.) The power port. When I plug in the power cord the blue light around the power port comes on fine and there doesn't appear to be damage anywere.
I also took out the motherboard with just the CPU on it and tried turning it on that way, but still nothing so I don't think this is a ground issue. I also tried the old motherboard that I replaced and even that wasn't getting power.
Double check your power connections, as like you said there appears to be a power issue. Maybe a wire came undone from the PSU when you were putting it back together? When you tested it and it worked, did you have it in the laptop case itself or did you have it out side of the case? It's acting like a ground issue to me. If possible, take it out and try firing it up while it is sitting on a book or something just to ensure it isn't a grounding problem.
Thank you for the response. I removed the motherboard completely and put it on a toil and tried to fire it up, but still no power. I removed the power board and examined it and everything seems to be intact. If this is a dead CPU, would the CPU fan still come on or wouldn't the PC still show signs of life? I really don't think its the motherboard though because what are the chances of having the same issue on 2 different motherboards.