For step 31 I had a problem where the screws with the springs just kept turning. While I did not have this problem the first time I disassembled the board, it was because I did not tighten the screws on the board (the studs on the actual logic board, not the ones you use to fasten the heat sink to the board) before reassembling. If you encounter the same problem, the screws aren't necessarily stripped but the actual piece attached to the board has become loose and just keeps turning. To get them off I used Vise grips and pulled up while turning until i got them off and it took a while. Moral of the story: tighten the pieces actually attached to the board before reassembling. Sorry, I don't know how else to describe the types of screws used but the stud is attached to the board and that is what came loose.