Problem summary and solution: The spikes stopped unretracting because the DB25 connector came loose from the back of the computer where it was plugged into the computer's parallel port:

Hello, my name is Loren... We have been having a problem with Seat Sale since yesterday. After the video is shown and the user is alerted to stand up, the buzzer will not stop buzzing and the spikes on the chair don't go back up. I looked at all the wiring connections and everything seems to be ok....

After some back and forth (trying the diagnostic device drivers, etc.), it was found that the problem was simply a loose cable:


  I just pushed in the entire mechanism on the
computer end - the parallel plug and the phone jacks
going into it, so I don't know which one was loose. 
The two larger cameras inside the box don't seem to
transmit a very clear picture, but the smaller one
inside the box does, so I will leave that one plugged


Note also that problems with picture quality can be fixed by making sure the four best cameras are the ones being connected to the four inputs.