Shuttering on manual move

I owned a PRT for years and recently upgraded to a used PRS. I am using the control computer that the guy I bought it from used. When I set it up, I downloaded the latest control software and firmware update. When I was setting it up everything moved smooth. Here's my problem. Now, while in "K", when I try to move in any direction with the arrow keys, it shutters, jumps and sounds like everything is coming apart. If I type in a location in and hit "go", it moves to the position smoothly. It also cuts smooth. This only happens when I move it manually, either in "K" or just the arrow keys on the computer?? Any ideas or direction?
Thanks, Terry

Reinstall the firmware via UI. Then do a UR and be sure to pick the right machine configuration.

Thanks Brady. I tried that and it didn't help. My move speed is set at 4. If I lower it to 3, it moves smooth. That's a work around but very slow and I don't care much for work around's. One thing I noticed too is that it's losing it's location, almost like the motor is jumping teeth but the motors are up tight? Not sure where to go next??

I have a PRS and it dose the same thing after i have been running it all day dosn't do it in the morning
May Z Axes just started doing same thing