Q: Cursor remains in upper left of screen despite changing batteries and receiving mouse connected icon. What else should I do? Pretty sure that throwing mouse and/or iMac are NOT the answer.

Have you tried cleaning-checking the optical sensor on the underside of the mouse.

Cleaning your Apple products - Apple Support

haoleboy96789 wrote:

 

den.thed, It may have helped. i restarted the machine again.

You are welcome! Sometimes all it takes is a small speck of lint or a hair to foul up the mouse's optical sensor.

i fear that this iMac may be on its last legs.

Run > http://etrecheck.com/ and report back with the results.

Then if that report comes up clean, we'll have you run the > Using Apple Hardware Test - Apple Support