Are you sure you installed it in Windows 10?

Or maybe did you install it in Windows 7 or 8 before upgrading to Windows 10? Then the only way to get it back is to go back to Windows 7, install the program again, and upgrade to Windows 10 again. That's a lot of work, but it should be free.
Make an image backup of your current system to go back to if something goes wrong. And be sure to make a separate backup of all your data to get those back if the install if Windows 7 deletes them.