I am  getting rusty: many, many years ago I installed Mach3 on an XP computer.  Today the computer died:-(  I copied the whole Mach3 folder to an identical model computer.
Everything looks normal but the laser does not move. The display shows the desired movement.
After a while, I realized that I should install Mach3, not just copy the folder.  I installed it but still the same problem.
The LPT1 is enabled.  Presumably I am missing something obvious.
Bertho

Have you copied your xml configuration file to the right folder?

I copied the whole Mac3 folder.   I might have forgotten something.  I have been running Mach3 for 20 years but the PC finally failed.  I am using Mach4 on my mill so the Mach3 setup is way back in my memory.
Regardless, I transferred the harddrive to the replacement computer and now everything works.
Thank you for helping.

Excellent.