I'm hoping you guys can help me with this. I have an IMac Pro that I replaced the HD for my girlfriend. She lost all the data on the HD. She had no OS that came with the machine. I bought Snow Leopard v10.6.7 and tried to load it on this machine. It comes up with an error message, "Mac OSX can't be installed on this machine." Do I have the wrong OS? If so, which version came with this machine? S/N W8940KPX5PC Model A1311 Purchased in 2010 but is a 2009 model. Next question. Where would I get a copy of the right OS? I see they have Snow Leopard OS installation DVD's for sale at the Apple Store, but I am not sure whether it is the original OS.