You need to be careful mixing and matching software versions of the top board, especially for early stuff. 94-95. By late 96 up the software type is less problematic.
Your board sounds like an ID conflict. Can you do a reset 18? IF it won't move out of reset, it is a software conflict. If it does and still does not work it can be a bad bottom board. Burned trace, faulty diode, etc.. Boards are repairable. Bottom boards easy replacement. Top boards and chip you need to be careful of the software issues. G