I recently obtained a first-generation MacBook Pro (1.83 GHz) that has a keyboard that doesn't work. An external keyboard works just fine. So I purchased another original keyboard (same part #, fits perfectly), but have the same issue - only a few of the keys actually register when I press them. Has anyone had a similar experience? Is is a problem with the top case or perhaps the logic board? If anyone can shed light on the part that I need to replace, I would appreciate it!