Hello there, not a long time ago I bought a Macbook Pro Retina with Mavericks and since then it was used not only by myself, but, unfortunately, by some other students as well. Now that this time is over and I have my Mac all to myself I wanted to make a clean installation, since it is slowing down, especially when shutting down. I furthermore am afraid that, by not being cautious rather than by intention, some malicious program (or whatever is the proper name for it) could be on my Mac by now. So, this leaves me with two questions: 1. If I save all my files, make a new clean installation und put back the files, should everything be fine, or could, in case that something is wrong with my Mac now, this continue to be so, since the problem could be in one of my files? 2. Is this ( http://support.apple.com/kb/PH14243 ) the proper and recommended way for a clean new installation?