I have a windows laptop (Lenovo w520 running Windows 7).
It has a displayport output and i purchased a display port to mini-display port cable. I've attempted to connect my laptop to my 2013 iMac 27" and it does not appear to detect my laptop. I've seen on several forums that you need to select "targetted" display mode by selecting "Command F2", but the iMac still does not appear to detect my laptop.
iMac (27-inch, Late 2012), OS X Mountain Lion (10.8.2)