Constant kernel panics/ failed OS install

Hello, a few months ago my 2011 15" MacBook pro began to kernel panic about once a week and about a week later would do it a few times a day. Two weeks after that the hard drive failed to boot up and required me to wipe it and when I tried to reinstall Mavericks on it the download continuously failed and finally worked when I took it to one of our computer repair shops in town and he installed a clean OS, but about a week later the same thing happened and the hard drive failed again... This happened two additional times since, same problems installing OS and all, and I've replaces the hard drive twice still getting the same problems and the geniuses at the Apple Store told me to just get a new one and the computer repair guy I've been using is too expensive for me to keep going to him. Could this be a problem with the RAM. Before it did start to go I did notice it was getting excessively hot so maybe it could have messed up the logic board? I apologize if this isn't clear as I'm not too tech savvy but I hope it came across clear. Thanks...