My K2-CNC stopped responding to Mach3. Last night when I was finished for the day I sent the router back to its home position using Reference All Home, which is what I usually do so the table is clear. When I turned everything on this morning and Referenced All Home so that my Soft Limits were now set the machine did not move although the Z DRO was showing movement. I believe the Servo Controller is communicating with the Servo Motors because I can hear them twitching a little. I suspect MACH3 is not communicating with the Servo Controller. I have experienced this problem a few times before, but a restart of everything would clear it up. Not this time. I have also noticed in the past few days that sometimes when I do a Reference All Home the CNC will ignore the limit switches and will smack into the end of the carriage. (Luckily I have the speed set slow so it is not hitting hard and it triggers the E-Stop.)

I have checked all the cables, and the XY&Z are all sitting off the limit switches. (Auto Limit Override is ON so I should be able to jog off the limit switches anyway)
Ran the MACH3 DriverTest and that showed Excellent.
Check the XP System Settings to make sure the Parallel Port # was still correct and that the port was functioning.
Running the latest version of MACH3, and XP on a Dell Dimension with a built in parallel port.

Any suggestions as where to look next to diagnose this issue? Any insights would be greatly appreciated.