Will putting the wrong speed Ram in MBP 2012 ruin computer?

Here's what happened:

I bought a 15" Macbook Pro in June and about a week later, got some RAM from a friend that was in their previous year (2011) Macbook Pro (they had upgraded the RAM after they had gotten the computer the previous and were switching to the 2012 MBP too). It was 8gb 1333MHz DDR3. I, very stupidly, didn't think to check the required speed of RAM upgrades for this year's MBP's. So I proceeded to put it in my 2012 Macbook Pro and for a little while it worked great. My computer was faster and running fine. Then soon after my computer would start to freeze while using Google Chrome and I would have to do a hard reset each time. I figured this was a software problem so I switched to Firefox and my computer worked fine for a little while longer. Then about a month later every once in a while the computer would start to freeze again, most of the time while I was doing relatively non-taxing things, like watching videos on youtube or something like that. Then I got a game for it and it immediately started freezing more often. Then it would start to freeze more often. After that when it froze green pixelated artifacts showed on the screen (picture below) and jittered around.

At the same time as the aftifacts appeared the speakers would start to make loud crackling noises when it froze and only stopped when I did a hard reset. I upgraded to Lion and that changed nothing. I called Apple and they agreed it must be a hardware problem. So I took it into a CityMac (the closest thing to an Apple store in the city I live in) and they ran tests on it. Sure enough they confirmed it was the wrong speed memory. They said that they tested it with good RAM and it worked fine, but that my computer's hardware may have been affected from having the wrong speed RAM in for so long. So I got my computer back and switched my stock RAM back in the computer about a week and a half ago. When I did this I saw that one of the metal nubs on the underside of the logic board (I don't know what they are called) that spring in and out when pressed was bent and to the side. I am positive that I didn't do this when I changed the RAM the first time, and noticed it BEFORE I changed the RAM the second time. I thought it might just be a sensor so it would probably be okay and I switched my stock 1600MHz DDR3 RAM back in and then started up my computer. It froze a couple times that day, but I was hoping it was just a little bit of residual stuff from the old RAM or something. Then it ran fine for a week and a half almost, even handling dual screens on a Cintiq 12wx Graphics Tablet for hours at a time. Then last night it started freezing again very randomly but frequently. It will not boot in recovery mode, it gives me this memory error message every time: -1006D.

That's a long story, but I guess my main question is am I screwed? Can putting slower RAM than is required mess up the memory sockets? And since I put in the wrong speed RAM does that void my warranty for repair or replacement? I only have the 1 year warranty. Any help would be appreciated.