How To Wipe/Reset iMac G3

Alright, I’ve yet to find a good guide on this. Apple boards aren’t helping at all, and it seems impossible to find an archived post with my problems. Any help would be greatly appreciated.

I picked up 2 iMac G3s. One was bright blue, the other graphite. The blue one didn’t seem to turn on, and the graphite didn’t have a hard drive. I pulled the necessary stuff from the blue one to complete the graphite one, and got it to turn on and boot into OS X 10.2.
However, its got a ton of pictures, apps, printer files, and other stuff on there that I’d like to get rid of. Not to mention 10.2 is kinda…bad. I got a set of the Tiger CDs, but I ejected the drive and found an OS X 10.1 install CD. I thought I might try that (as I’m a sucker for old software), so I put it in and hold the C key on the keyboard. It blows past and boots straight into the existing hard drive. I also was thinking about Classic, so I put in a retail 9.2.1 CD. It would do the same thing, just blow past and load 10.2.

So, I went into the settings and changed the startup disk to the CD drive and got the following results:
-10.1 install would load, get to the disk selection, and refuse to let me chose my hard drive, with something about different languages.
-9.2.1 would show the happy mac, and then freeze. 5 minutes later, CD isn’t spinning, HDD isn’t spinning, and its still showing happy mac.

unless tiger is different and lets me access my Disk Utility, and the utility actually lets me erase the disk, I’m stumped.

PLEASE, someone tell me they can fix this, or give a way to fix it. I’m really tired of having to mess with this. I should be able to put in the disc, hold the key, and boot the CD, right? so what’s this about not booting it?

Just a bit too reto