Lightsout Client Disapeared After System Restore, Won't Reinstall

I had to roll back one of my clients for a problem unrelated to LightsOut.

The addin on the server did not notice, and thinks the client still had LightsOut installed.

Hence a request to install on all clients fails.

Any ideas besides uninstalling the addin on the server and reinstalling?

WSE 2012, Latest LightsOut.

Thanks,

Andrew