There is a small chip card below it that must be removed first. Then by swiveling the Ethernet card, reinstalling the chip card and wiggling the Ethernet card, it can be installed.
I am running Snow Leopard on my "July 2011" Mac Mini within Parallels 7 when I need to run my old PPC applications that require Rosetta; primarily Quicken 2002 Deluxe. Screenshot: https://discussions.apple.com/servlet/Ji...-16247806-39229/Lion-Snow+Leopard.jpg See my post on the Apple Support Communities