My computer only turns on with applied pressure, what's wrong?

My MacBook Pro does not turn on unless I apply lots of pressure on the right above the disc-drive. Before, I only had to apply pressure to turn it on and then it would stay on, now it does not stay on unless I apply consistent pressure above the disc-drive. Apple told me I had a faulty Logic Board and my warranty is expired. I feel as if there is some misplaced circuitry in my computer. What Step-by-step guide can I follow to fix my computer so that it can turn on? And what is wrong with my machine?