I have a Late 2008 MacBook Pro (Unibody) running Mountain Lion. Whenever I start up the computer, a part of the right side of the screen has lines that move and flash. I know that Apple came out with a driver that would stop the flickering of the internal display on these MacBooks, but when I try to install it, it gives me a message saying that my Mac doesn't need the driver. The lines only appear when I boot; they go away when the Apple Logo moves up so I can log in. Any help is appreciated. Thanks!
MacBook Pro (15-inch Late 2008), OS X Mountain Lion (10.8.3)