Recently widowed neighbor wants me to fix her Macbook Pro 15

[chopper]

It's very very slow. I did a new admin account and it is still very slow.

Might anyone know what OS this beauty would run if I did a nuke and pave?

Ordering a replacement battery from OWC now.

[hal]

That's a FINE 2012 top of the line model

it should not be slow - replace the hard drive and install an OS - Catalina is the last one it can run officially.

PS: check the drive with SMART Utility

[numbered]

Yes, the great last unibody before Retina. First with USB3. As Hal said, can handle Catalina...with an SSD. Can handle 16Gb of RAM.

My beloved spouse still uses this as her daily driver, on Mojave.

Opening to replace battery, RAM, drive is no big deal.

[Forrest]

You have a highly desirable mid 2012 MacBookPro with the upgraded i7 CPU. This is the last MBP that’s easily upgradeable. If i’s slow, it’s probably the hard drive. The 500 GB, 5400 rpm spinner may be on it’s last legs. You may want install a 2.5 inch SSD for better performance. I would install OSX 10.14 Mojave because of 32 bit compatibility.

[anonymouse1]

Assuming it's not Retina and has a replaceable spinny hard drive, put in an SSD.

ALso, how full is the HD/SSD?

Sudden motion sensor enabled suggests it's a spinny drive.

[Ken Sp.]

How full is the disk?

[Paul F.]

Backup that drive immediately.
Then see about getting an SSD in there...

Then update to Catalina, import from the backup.
Boom... almost like a new one!

[Carnos Jax]

Can’t stress enough upgrading to an SSD. It made our 2009 C2D MB eminently useable.

[mattkime]

Is she your type??

[anonymouse1]

New SSD first!

Then, optionally, 8GB of memory is good; wouldn't hurt to bump it to 16GB down the road. Not necessary, though.