Why is my laptop's lightbulb going off and then making it sleep?

So around New Years, my girlfriend and I went to NY and I don't know why I am telling you this but there was liquid damage. We took it somewhere to get it fixed because it worked for a while and then decided not to work at all. They ended up cleaning the inside and it worked fine with a few weird things happening until now.

So I was doing a little bit of research and it seems that the computer's back lightbulb keeps going out and then making the computer go to sleep. But here is the kicker. It only goes out if the laptop is plugged into charge, but will stay lit if the mouse is moving. It will go out, then you have to click it a few times, then it lights back up for awhile until you stop moving the mouse.

The laptop also decides to only hold a charge every once in a blue moon. It is fine when it is not on the charger, but when it is, the green light on the charging port doesn't light up, so it doesn't charge. It only keeps it alive, but makes it go black.

I would love to know if there is anything I can do so we do not have to take the laptop into apple because I am in college and don't have the money, nor the time.

All input is appreciated. Thanks