I have an old, pre-unibody 17" MacBook Pro. It is currently running Capitan. I have older software I need to run and want to go back to Tiger. Every reboot option I attemp will only let me reinstall Capitan. I have no Time Machine backups but I have a good install disk of Tiger that the virus-like Capitan will not let me boot from. Already did my backups and am set to go if I can boot in any non Capitan OS.
TIA for any help.