Hello, I have received a macbook pro retina display - early 2013. The problem with this macbook pro is that the trackpad is laggy. The desktop loads very slow. After a while the screen just moves from the desktop screen to the widget screen. The computer stays on if on charger, but if unplugged, after a while would just shut down. I cannot find the board number on the board. What is that I need to check to fix this computer.