Chosen Solution
The battery you sold me makes my computer do wonky things now. Can’t do simple tasks….
Let’s run the onboard diagnostics to see if any errors pop. Restart your system and press the D key to enter Reference: Mac startup key combinations If that doesn’t show any errors then I would replace the HD SATA cable as they do fail quite a lot! Your Hard Drive Cable Is A Ticking Time Bomb So I would place a strip of electricians tape down to help isolate the cable from the rough aluminum surface but I would still replace the cable MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable and here’s the guide MacBook Pro 13" Unibody Mid 2012 Hard Drive Cable Replacement Make sure you don’t crease the cable as that to will damage it!
Paulette. I don’t think changing the battery for the laptop will increase performance. you might want to get new ram or upgrade your ram and possibly get an 2.5 sata ssd.
