I have been running Mach 2 for a couple of years with very good success. I recently upgraded to Mach 3 R2.45. I am running a 1GHz computer with XP Pro. Everything seems to be working OK with the exception of the fact that the motor step pin numbers keep changing. I will correct the pin numbers (the step pin numbers are the ones that keep changing) and try to dry run a program. Most times the X axis (I am running Mach 3 turn to drive a 9 x 20 lathe) will stop moving in the middle of the program. When I check the pin assignments they are changed to something random. I tried running Mach 2 provided with this release and have the same problem. This is a licensed copy. Thanks for any help you can provide.