Need help Trouble shooting X axis will only move one direction

All,

I am new to CNC and need some help getting my machine working again. I have been using it for two months with no problems using for woodworking projects. I have about 100 hours of use on the cnc

I am running Mach 3 and all my G code is generated thru artcam.

I have a made in china 6040 with 4th axis which I have not used yet.

I was cutting out some inlay pieces which the program takes about 1 1/2 to complete. I left my machine running for 20 minutes and came back and my X axis went postal.

It jogged all the way to the left my negative and would not move back to the right. My arrow keys all work except for the right arrow key when pressed it moves to the left. The Mach 3 program showed the arrow keys working correctly

I thought I might have a bad motor and swapped x and y cables and still had same problem the right arrow key went opposite direction on other motor.

I opened the cnc control panel and run some air thinking my wood dust did something NO LUCK.

ANY HELP OR SUGGESTIONS WOULD BE GREATLY APPRECIATED

Thanks

Jeff