Two Questions: Macbook Pro 2011

[eb0819]

1. I have a 2011 Macbook Pro that will not turn on without being plugged into the charger, but once it has booted up it can run just fine without being plugged in. This wasn't a huge issue for me, until the next one happened:

2. Now, recently it has started to run super laggy when the charger is not connected, and the CPU load will jump to near 100%, causing the fan to turn on full speed. It runs so slow it's basically impossible to use. But once the charger is plugged in the Macbook calms down, fans slow, and runs just fine.
^^^This problem has happened about 2 years ago and was corrected by going in and deleting one of it's .plist files, but when i tried doing that most recently I got an error message that the file could not be deleted. So now I feel kinda stuck (to an outlet) Any advice is appreciated!

 

[Camarillo Brillo]

Definitely sounds like you need a new battery to me, but let someone more knowledgeable reply

 

[profcutter]

Yeah, you should check the battery health. It’s normally in a pretty sad state when these kinds of problems start happening.

 

[eb0819]

I'll have to check that out, I initially didn't think to because it would hold a charge after it turned on with the charger, but now since it won't run properly without being plugged kind of changes things a bit. Thanks!