I own a Computer repair business and deal with just windows computers but i have a good customer that wants to upgrade his Powerbook G4 from Panther 10.3 to Leopard 10.5, i got a disk of off ebay but i think it is the wrong one, it's called a Mac OS X 10.5 CPU Drop-in kit can i use this or do i need the retail disk. Thank you to anybody that can help.