I've borrowed a imac disk from a friend, the version after the G5, but after restarting, I get a message error after restart saying "this disc cannot be installed on this computer" or something similar. Anyone help?
If its a grey disc its only for the machine it came with. You need a full retail version of the OS you plan to install. Or the install disc for your computer model. And do not use words like borrowed on the open forum.