On 25 Sep 2010, at 11:48, Geoffrey Heard wrote:
> Help, I can't remember how to change the stART-UP DISK.
>
> I want to change to booting from my USB backup disk so I can "restore" stuff in my OS.
You can change your startup disk from System Preferences=>Startup Disk, and restart the computer.
If you just want to change your startup disk once, restart the computer and hold alt (Option) key until all bootable disk icons appear. Then select the icon of the disk you want to startup and let go the Option key.
Hamid