I bought a new keyboard and mouse, cheap ones, just in case I did just that. Of course, this is a prophylactic against it ever happening.

Red wine causes remotes to misfunction, in my case, continually running the batteries flat. Stripping (carefully) and cleaning (Electro-Clenz or CRC) will sometimes fix both items. It might even improve your shift key.

Why are flat batteries still round?

No-one threw them away.

Sorry.