I have an old Imac that i want to sell. But first i want the entire computer clean. I've got the Mac OS 9.1 CD. There are two hard disks in the computer. On the first one i've successfully did a clean install of Mac OS 9.1. But the other hard disk is read only. I can't format it with disk tool. I've also heard it's possible to boot from the CD, but i don't know how to do this.