My 15" Macbook Pro (early 2011) has been freaking out and I'm trying to find out what is wrong with it. I was sending some emails and suddenly my display started to bug out and the computer shut off. I could not get it to boot back up again. When I turned it on, it would take me to the log in screen and after it would just stay on a gray screen. I did the AHT and the report stated that I have a 4mem error (memory). I then tried booting up twice with one memory stick each time and I still could not get it to work. I then reset the NVRAM and the computer booted up. I thought everything was fine, web browser and other simple apps were working fine. Then I opened up Avid Media Composer and the display freaked out and the laptop shut off again. I tried this several more times and the same thing happened with the video editing software. I've included some images of what I've been seeing. Just want to point out that about 2 years ago Apple replaced everything inside the computer, as my laptop was part of that graphics recall. I had the same issues back then, but Apple was able to take care of it. The only difference was that back then the computer would not boot up at all. Any idea what's wrong?