Can't override passwords or re-install on old Imac

Hey..I just bought an old iMac for my dad for like $20 on ebay. Trouble is it requires passwords which the person didn't who sold it to me didn't know. I figured I could just get an old os 9 install disc and start over. BUT..when I pop the disk in, it just spits it out. It doesn't recognize it. (The imac is running 9.2 and the install disk is 9..could that be the problem)? The CD drive works because I popped a regular audio CD in and it saw it fine. I tried restarting holding the "c" key down before it had a chance to spit the disk out but that didn't work either. Is there anyway to override these **** passwords? I just can't understand why the disk wont mount. It mounts on my current Mac so it's not a bad disk. Help this sucks! Thanks

Pop the disc into your newer Mac, connect the two Macs via firewire, reboot your newer Mac and hold down "T". The boot the old iMac and hold down "option". You should be able to boot off the CD in the newer Mac's drive.

(assuming of course the old iMac has firewire and you have a Firewire to firewire cable).

Thanks Apt but the old Imac does not have FW. Any way to get the 2 talking via USB?

Hmm, unfortunately not like the way I described above - that's a feature that only Firewire offers.

I don't think your can boot PowerPC Macs off of USB harddrives either... don't suppose you have an old external CD drive lying around?

no i don't. but thank you much for your input. perhaps i'll take it to my local apple store and see if they can do something.