Stepper motors not moving

Hi y'all - help req'd please!!!

I have had my Chinese cnc for a three/four years now and for the light weight work I do it's doing a great job however.......
Because my workshop gets cold (November through to April - in Scotland) I bring the pc and controller into the house when not in use, fire up the heater in my workshop before bringing them back out once the temp inside reaches 15C+. Been doing this since I had horrendous issues with the pc/ cnc machines not working properly in cold temps (below 10C).
Today I decided to do some work. Once the workshop was warm enough, brought out both pc and cnc andplugged everything in.
PC/CNC software (Mach3) fired up okay and is working fine. When I switch on the controller the water pump kicks in and all 3 stepper motors receive power (difficult to move manually).
When I try to move any of the axis using the keyboard keys as normal I can see Mach3 working but there is no movement in the stepper motors
I use windows XP connecting a Dell pc to the controller by means of a 18 pin cable
I have treble checked all connections - XYZ cables, cable from pc to controller but it all seems fine. As mentioned I have been doing this for a number of winters Has anyone come across this issue or is there anything else I can check? I am beginning to think its the cable connecting the pc to the controller as everything else seems to be working

cheers Steve

Doubt it will be the cable. Usually a dodgy cable will work but give strange results.
Mach will work just has if the machine was alive because it knows or told no different so it will be sending pulses just the same but no ones listening.!!

Chances are it will be either a BOB or Drive problem. Possibly a blown fuse to PSU for BOB which would stop all signals going to the drives.
Or has often the case with these Chinese machines if using TB based All-in-One drives and if not PSU related it could be dead.!!

Could be a Broken wire so look very carefully.

Thanks Jazz. Just tried to uninstall and reinstall Mach3 but something is wrong either with the PC/ drivers or the software. Now getting a blank page where the different tabs and screens should be!!!
will get a sparky to test the controller though
Thanks for your input