Most Key Remapper licenses are per-user, not per-machine. You can deactivate on the old PC ( Help > Deactivate ), then install and activate on the new PC using the same serial.
The program will verify the data and remove any trial limitations. Important Security Note key remapper serial number
Are you trying to you previously bought, or Key Remapper - ATNSOFT Purchase Most Key Remapper licenses are per-user, not per-machine
If you've purchased a key remapper, you can usually find the serial number in one of the following locations: Most Key Remapper licenses are per-user