Curser problem

[CloudWatcher]

5. Might be the battery

Perhaps you've spilled coffee on the trackpad?

But ... unless you've replaced it, the battery in a 2012 machine is likely bad. In addition
to not holding a charge long, it can swell up and get substantially bigger.

Quick no-tools test: Put the laptop on a flat hard surface. Push on each corner (one
at a time) and see if the machine "rocks" or lies flat on the surface. If it rocks (not
just due to missing feet/pads on the bottom), you've got problems.

Old batteries will often swell. The result of it swelling include:
(1) pushing out on the bottom of the case; results in it not laying flat.
(2) pushing up ... often hitting the trackpad or other components.

Old batteries can be replaced with kits from iFixit, but it's not for those
without some serious willingness to work with tiny and breakable parts.

Ofc it could be any number of other things, but I've seen way too many
swollen batteries in my old laptops!

Good luck!