If you click File | Online | Check for Update and download the update, but then cancel the installation (or there was an error), Surfer is no longer installed. You can use the downloaded EXE to rerun the update and reinstall Surfer. The location of the file on Windows 7, 8, and 10 operating systems is C:\Users\<username>\AppData\Roaming\Golden Software\Surfer.
To begin the installation procedure, navigate to that folder and double click on the installation EXE file.
Updated November 2021