Need help on 1 Macbook Pro, and 1 Macbook original.

Okie Dokie. So on ebay I brought a Macbook knowing it was broken, mainly because I like a project. I haven't recieved it yet but in order to prepare myself for what I am about to face in my project, what can be the possible cause for a Macbook to just stop powering on, besides the battery?

Also, I bought a broken Macbook pro, This one just has a bad battery and the Argyle Checkered Screen problem.

I just want to know all the possible fixes for these issues.

I'm training to be a Computer IT or a genius an apple store. I know it requires actual training but I just want something to get my foot in the door.

I know it sounds silly. In fact these 2 macbooks might still be under warranty. However, I just like a project.

They were $250 all together.