How do I fix certain keys on my keyboard?

This is for a Santa Rosa machine.

There are two macbooks. Computer one works good enough

Computer two had a broken inverter, which I changed, and a keyboard with a broken left shift key, a broken brightness up and brightness down key, possibly a broken fn key, and most importantlya broken power button

Also, there is no display and no sound that should happen when I turn is on but that is unrelated.

I recently changed the inverter board on computer 2, and apparently, I hurt the keyboard in the process. (of all things)

I tested many things, and I know that the other keys work, as well as the trackpad, and clicker.

Any and all help is apprectiated.