Thank you all. I reinstalled mach3 and i had problems with the motors again for some reason, I replace the motors with ones that have more power and work find even with the current cut way down. I think that I burnt the original motors when I live the idling for long times with the machine on but not having anything moving.
Is any command to cut power to the motors after the end of the code? 

Sorry; however, I forgot a detail that may be significant.
Before, when I was running the demo version for about 3 years I never had the motors locked up, with current flowing, after the program stop or before start..... is there some difference in this regard on the register version and the demo one?

Is any command to cut power to the motors after the end of the code?

Not within Mach3 but most motor drivers (ie.. TBA6560 etc.) incorporate a reduced stand-by current setting.

Best to adjust your driver current setting so that your motors outside case temp never exceeds 60 deg.C (even when stationary for long periods).

is there some difference in this regard on the register version and the demo one?

There is no difference between the licensed and demo versions of Mach3 in this respect.

Tweakie.

I will check the option of reduced current on stand by. Right now what I did was to install  bigger motors than needed ar a reduced current; they are working just fine but I am afraid and I turn off the power supply to the drivers in standby.

Thank you all for everything, and being willing to share with us ,"newbies", your knowledge and experiences.
Mtabernig