I would disassemble it again and check/clean the keyboard connector
try to remove the cd while pressing the "mousbutton" - if that wont work, use a usb mouse and hold the left button pressed during bootup.
since the password prevents you from seeing the working/nonworking/falseworking keys - remove the password with the setup dvd - [http://www.creativetechs.com/iq/reset_a_lost_mac_os_x_password.html|click here for the instructions] (do almost everything as shown - but don't enter a new password)
when the computer booted up, use any program that is capable of showing text input to see wich keys are working properly and wich are not