I've had my MBP for the past 1.5 years or so and it's been a dream. It's a 2.2 Ghz Intel i7 Quad core. I upgraded the RAM to 16GB myself later on. Lately when running apps, the screen either goes black needing a hard reset or the screen is black with green stripes or it distorts into 2 and the system is un-responsive again requiring a hard reset. When booting up, 2 out of 3 times it'll get stuck on the white, gray screen after the apple logo. Does anybody have any idea why this is happening?