I have a Compaq V2000

Question

I have a Compaq V2000 laptop that you have to push down on the heatsink to get the pc to start up. Sometimes it will stay on...sometimes it won't. If it does and you move the laptop at all, it will go off. I have removed the cpu and reseated it and then reset the heatsink but still the same problem. How can I get this to work right everytime without having to push down on the heatsink?