If you are selling your iMac and would like to leave it like new for the next user follow these instructions. Re-install Tiger and restart your mac, you will then be presented with a language selection screen. Choose your language e.g. English (this is just temporary). Then watch the intro movie and let it complete, at this point it will start to ask questions about setting up the computer. Just press the Command key + Q, then a message box will appear giving you the option to cancel or shutdown. Click Shut Down. Next time your mac starts the user will be right back at the language selection screen - Just like a new mac!