Have been using an X- Box on my table for a good while with no problems. Got the controller off of EBay, installed the download from Art Soft, Microsoft and so on. A wire in the USP cable from the controller broke and it has quit working. Can move the cable around and it will make connection, then drop off again, so I know it's in the cable. Got a new X- Box rock candy controller from a local store and can not get it to work. I have uninstalled all software related to the old controller and reinstalled everything, get green light on controller, but I have no control of Mach3 at all. Any ideas? Thanks muchley!  

I tried the same controller with the same results. I then read that it has
to be a Microsoft X-Box controller only. I got one and it works great.

OK, got it fixed.
Not sure if this will work in every case, but did in mine, or this case.
Open the Plugin Control and Activation box where you configure your plugins.
Click on the CONFIG tab to the right of your XBox you want to set up.
When that box opens, you will see a place to enter a Vendor ID and a Product ID.
If these are filled in, you would, or should be OK. If they only have "0" in the boxes, you will to enter something.
I used some # I found on a web site and it started working after I restarted Mach3.
Don't know if it will work for all controllers, or not, but here they are
Vendor ID: 0E6F
Product ID: 011F
Like I said before, don't if it will work in all cases, but did for me.
Good luck, and thanks