I have a client that brought me an HP Pavilion DV9000 laptop that he reported was "freezing" and having "odd issues" with the screen. Now it simply does not power up at all. The lights above the keyboard all light up, but after a minute or so turn off and then turn back on. Connecting an external monitor did not work, so I don't think it's the screen it seems like maybe a graphics card/motherboard issue.
I tried doing the full power cycle (remove battery, hold power for 10 seconds, try powering up only plugged into AC adapter without battery) and it did not fix the issue. I'm leaning towards this being a motherboard/graphics card issue and am about to recommend a replacement motherboard for the client, but wanted to make sure this sounds like an accurate assessment before I do so.