I would like to know what it is and what I can replace it with if this part is no longer available (I just checked the many PCB's I have here and none of these to be found).
The damaged component appears to be E632, which is a 100pF feed-through capacitor on the keyboard clock line. That won't prevent the computer from booting, but if it's open circuit, will prevent the keyboard from working. There should be close to 0 Ohms between pins 1 and 3, and no connection between pins 1 or 3 to the centre pin (ground). The component performs decoupling of high frequency noise on the keyboard clock line, and the system will absolutely work fine without it. If the part is damaged (open circuit between pins 1 and 3), then you can replace it with a wire link between pins 1 and 3. A standard 100pF capacitor (2 leads) is not a drop-in replacement a feed-through capacitor (3 leads).
A brief read of this thread suggests there are obvious IC socket corrosion issues. In which case replace them first, clean IC leads as necessary, and look at any remaining faults after that.
