I've been using Mach3 in Demo mode for a while to run my bench top milling machine. I've been using Probotix breakout board and drives. I he'd a short in the wire from the "z" axis drive card to the stepper motor.  Everything ran okay after fixing the short for a couple days. It them would miss steps in one direction of the 3 axis. I thought that it may have caused by the short. Thinking I may have also shorted out the parallel port I hooked everything up to another  computer . I then downloaded Mach3 again and loaded it to the new computer. Nothing worked . Thinking maybe I shorted out the breakout board so I replaced that and still have the same issues.
When the power is turned on to the breakout board the motors lock up as normal but still no movement. Any suggestions?