Where is my Gizmo?

Disaster has struck. When I go into Editor/Build, my Gizmo does not appear. I cannot "select" anything either already in place, or from the menus. The only thing that has occurred is the following. Whilst doing some admin in my assets folders, my cat jumped on my keyboard which was on my knee. Before I could do anything, my bin files were "associated" with Notepad [In file-->properties you can select an application to open files; usually bin files do not have them]. I tried to "un-associate" but that does not seem possible. When I went into RW, the problem of no Gizmo surfaced. Nothing I did could bring it back. I have had a look in the Railworks folder, and the only file amended around the time was "WrapperSettings.xml"
Anyone got any ideas?

Frustrated of Larbert

Where is my Gizmo?