How do I get past the Apple logo screen?

I successfully repositioned the center button's rubber pad thinking that it would solve my problem. However, the Apple logo appears on the screen and will only go away momentarily when I do a reset.

It won't go into disk mode and won't go beyond the apple. I hear no clicking or whirring either. I've opened it back up removed and reinserted the hard drive connector as instructed on my original button question post but the Apple logo remains constant, taunting me. This last time, the battery was dead when I put it back together, but it knew enough to put a message on the screen of 'please wait, very low battery' so is that a hopeful sign of something working? There are so many parts and I'm so clueless on diagnosis that I don't want to try (buy) a bunch of used parts only to discover that the thing is unfixable. May as well buy a brand new one to have something work for sure in the end.