If your Scan&Solve toolbar no longer appears in Rhino, you can manually add the toolbar by following these instructions.
First, navigate to your Scan&Solve Appdata directory by opening Windows Explorer and entering %Appdata%\Scan&Solve\ into the navigation bar.
Second, open up Rhino. Drag the ScanAndSolve.rui file onto the Rhino window. This will open the Scan&Solve toolbar, and it can now be docked back into the Rhino interface.