So, in 2007 I received a 17in iMac for my Birthday, then in 2010 I won a Macbook 13 inch from my school, so my dad made me give my iMac to my sister. Well yesterday was her birthday and she got a 13 in macbook pro. So I got my iMac back. Well before christmas, I bought my self a Mac Pro for Final Cut Pro and some heavy duty processes. I really don't have any use for the iMac, and I'm not going to get very much for it if I were to sell it because my sister some how managed to have it fall of her desk. It works, it just has some wavy lines on the side it feel on. Nothing to managed, God help that Macbook she got, I hope it lastes longer then her phones. So I'm thinking I can use it as a secondary display, can anyone tell me how one might go about doing it?