Re-install it.
Activate using the same key, if activation isn't successful email softwrap.
This is discussed on the YoYo Games
Help Page:
QUOTE
Q: Having bought GM7 Pro, how do I install it on a 2nd or 3rd computer?
A: Download GM7 Lite to the PC, run the program and click on the 'Enter Activation Code' tab, then choose 'Reinstall Existing License' and here you may enter your details. Remember to put the email address used for the purchase as License Holder