I have an IBM PC 365 model 6589 Pentium Pro. I recently added a writeable CD added 40 gig HD and installed internal modem. It currently has 64M RAM. We tried to increase memory by installing 2 64M PC100's but they won't work. Looks like we need to replace Motherboard first. I need to find out what is compatible and I don't have a clue where to start. Can anyone help??