Now you should have fixed your problem, but we should make sure its fixed.
Plug the RAM chips into the slots
Plug the HDD into its plug
Hold the HDD and flip the board over so the HDD is on the ground with the board ontop of it.
Connect the power button pad to the motherboard with the zif cable.
Connect the video wire into its socket.
Connect the pad with the charger socket to the board.
Plug the charger wire into the socket and press the power button!
wait for the LED's to turn on!
wait for the compaq logo to display!
If the logo and some bios information come up then you have a fixed laptop. IF it does not appear I don't know whats wrong :/
But if it does not work don't be afraid to ask questions, myself and im sure the rest of the members are willing to help.