Lets me out for testing - I have an older version.
Let's clarify something: You discuss the idea that when things go funky on you, certain mouse functions no longer work in Access. But your choice of words left open the possibility that the mouse is still usable for other things like selection preparatory to launching something, for mouse clicks on a control, etc. Is it the case that for Access, once the problem manifests, the mouse is not just merely dead, it is really most sincerely dead?
When you dropped the old mouse in favor of a new one, did a device driver disk come with that mouse? OK, mouse drivers are pretty generic, but some vendors add bells and whistles depending on connectivity methods. You DID say you uninstalled and re-installed the mouse, which sounds like maybe a driver was involved. Are we talking USB? Wireless? Blue Tooth? Some other type of connection? How does the new mouse commune with Windows?
Another question, though that little test DB makes it unlikely... have you tried creating a new app from scratch by importing everything to a new blank DB file? I'm working on the idea of DB corruption even though that little DB says "poor odds."
Then there is my old standby. Launch your DB. Attempt to use the mouse on your Access DB. Carefully note the exact time on the computer clock (usually lower right end of task bar) as to when you make the attempts. Then open up the control panel and get to the administrative tools section. You want to launch the event viewer and go through the System and Application and Device logs looking for any kind of mouse-related event at the specific time that you tried to do something. If you find something, report it.