I've been having some issues with the retina macbook pro 15 (Scrolling was noticeably choppier, brightness settings were out of whack) So I decided to reset the pram and the smc. I didn't have any issues when I reset the Pram but once I set the smc, a large block of artifacts that flickers showed up middle of the screen as the laptop displayed the apple logo. I tried restarting multiple times but it's still there. Is there anything I can do to fix this or should I book a appointment?