PUMA 500 Series Robotic Arm

Recently I was hired to set up and if necessary repair a PUMA 560 robotic arm. The arm itself is a six axis manufacturing arm, that is controlled by computer. There are two methods of control with the original system, the first is by programing in VAL (variable assembly language), a series of points and rotations where you want the machine to move too. The second method of control is to use the teach pad with which you can turn any particular joint on its own or move the arm as a whole, once the arm has reached the desired location you can record it onto the computer.
The sequence to start up the arm is fairly simple, all the breakers need to be checked to ensure that they have not been flipped, power is plugged in and the the main break is turned on. When I first flipped the switch i found that the computer was getting power but not loading. In order to troubleshoot this I had to manually check the circuit boards. What i found was that one of these boards was not properly inserted and probably had not been for a while. Reinserting this board was quite difficult due to the overlapping connecting cables that crossed in front of it. When the board was finally reinserted, the computer would still not initialize. The next step according to the manual is to replace the boards which is not an option.
If the system does not initialize, the arm will not activate. So in order to get the system to be useful I now need to come up with an alternative to using the original computer. The two options that i have been investigating so far are connecting a new PC to replace the old one, or creating a completely different control system for this. Most of the information I have found pertains to creating a completely new system.