I have an early 2011 15" MBP and it's been having a lot of problems. 4 months ago I replaced the RAM -- 4GB to 8GB. Since then I've been having a bunch of problems, but I don't know if I can really attribute them to the memory change. I bought a highly rated RAM stick from NewEgg. Anyway, every once in a while my trackpad and keyboard will be completely unresponsive. If I'm watching a YouTube video or something then it will continue to play, but I can't move the cursor or type anything. Basically, the only thing I can do is hold the power button until it restarts. But restarting is a problem all its own. When I restart it usually restarts well, but sometimes it will take an exceptionally long time... so long that I just give up and try again. Other times it will beep three times continually until I restart it (sometimes a couple of times) to get it to boot up normally. So far the only thing I've tried is taking out the memory and putting it back in. Does anyone have any ideas as to what could be wrong?