I did this. It does work but when I restart I get the darn problem again.

Its a weird problem. But I think it’s not just the mouse. It could be other stuff USB. You could be right. I will check with Windows 10 (garbage on a second boot drive)

My biggest complaint about calibre-web is that you can’t search for text inside the books you’ve got. It has to be a surprise! LOL.

Its both the front and back of the computer.

Have not tried BT.

Yes. It will work each time I plug it on a different port until a few minutes later.