Resposta para "How to replace the battery"Thanks Pat Downey! Those can be purchased from alixp (no affiliation whatsoever) for the price you mention. Some of the listings include the star screwdriver to open the mouse. https://www.aliexpress.com/wholesale?tra...-000088<ype=wholesale&SortType=price_as...
Resposta para "right click does not operate"I think that my right click button, being the one that is used most, is probably mechanically broken. As a stop gap measure, in Control Panel > Mouse, I can set the two small side buttons (usually for zooming and returning one page in a browser) to function as (right) click buttons. Unfortunately I don't seem to be able to set a click of the wheel to function in the same way.