Hi Guys, I hope you can help. I bought a Macbook Air from ebay. The guy I bought it from includes a copy of Leopard on a USB stick which he said is formatted correctly. I checked this buy putting it into another mac and you can see the install snow leopard icon and was GUID partitioned. Now when I put It in the mac and boot it up and I dont get the option to boot from the USB and install. (the guy erased the HDD before sending). Instead it says install Lion but then asks for itunes user name and password to install. I obviously dont have this and wanted to install leopard from the USB. I have tried holding the options key to get it to boot from the USB but end up in the same screen where I can install lion, go to disk utility etc. Any ideas guys?