formating HD question

question... ive sold a iBook and id like to clear off some of the crap ive put on it so its back to day one. it has 10.3 on it, however, alls i have is a Tiger DVD disc. its a G3 500 mhz iBook that only has a CD-R in it. i have an external USB DVD writer, and i can plug it into the computer and the dvd shows up, however, when i try to reboot the system, the computer doesnt acknowledge the external DVD until OSX is booted up.

so ive pretty much quite trying to put tiger on it until i send off for some CDs of it. however, i need to just wip the system clean and do a clean format back to factory settings. is this possible without an OSX disc? thanks in advance.

put the tiger dvd in the usb writer. when os x boots up open sys prefs and select the writer as the startup disk. then reboot and see if it boots to it.

I'm not sure if that'll work... AFAIK macs can only boot from internal or firewire devices.
You could try popping the disk in another running mac (assuming you have access to one.) then hook the 2 up with a firewire cable and boot off that.