G5 Restore

Click here and follow the instructions. When you reach step 5, insert its original disk, restart with the C or Option key held down, use the Disk Utility to erase the internal drive, and install a fresh OS.

(124502)

By use of the original included software install restore DVD set the computer

may be restarted (hold C key down while booting with DVD in optical drive)

and that should eventually start up with the Installer on view in display...

You need to note there are menu options across top of Installer, like in Finder.

So you can choose to use Disk Utility and options within it, to perform tasks

that pertain to erase, secure erase, install, reformat, etc. You could look into

the secure erase if you are going to give or sell the computer to someone.

How to prepare your Mac for sale (or restore to original software)

http://www.thesafemac.com/how-to-prepare-your-mac-for-sale/

http://computers.tutsplus.com/tutorials/how-to-sell-your-mac--mac-31635

By secure erase, the Disk Utility may be allowed to over-write the content of

the hard disk drive, with Zeroes; this would make earlier content less likely

to be problematic with a later installation and also later users or owners may

not be able to find your old content. Usually after this, a reformat is done so

the computer knows where to load the software.

Anyway, the basics are the same if selling, giving away, donating or recycling

(for further use, is best recycling) of a Mac computer when you have original

install-restore DVD media that shipped with the computer, or with later retail

version of the OS X that is running in it; be sure to include system DVDs with

the computer wherever it ends up. They are considered part of the computer.

Good luck & happy computing! 🙂