If SignCut won't start for some reason then you do not need to uninstall and reinstall. There is an easier way. 

Please follow these instructions:
1. Open any folder on your computer.
2. Type %appdata% into the address field and click Enter.
3. Locate the SignCut folder and delete it.
4. Restart SignCut and enter your license number and cutter settings.
5. Close the program then restart it and all the information you entered should be saved in the program.

Here is a video that shows this process.

If you do not have your license recorded you can recover it via email by clicking here