I presume the laptop has W10. I have an acer ES-!5 quad core and basically all it is good for is a doorstop.
It uses half the memory when it is just idling CPU and disk usually running up to 100% quite a lot of the time. Battery is inside the laptop so would be hard to get to.
It just does not want to know what security programs I want to use on it. So basically you are stuck with Windows Defender.
Apart from running C Cleaner or giving it a defrag there is not much more you can do with it.
Maybe get rid of Windows and put Ubuntu or something like that on it.