iMac G3 wont boot Mac OS Cd's

I recently aquired an iMac which had a dead hard drive. I replaced the 60 GB maxtor with an old 6.4 GB quantum fireball I had laying around just to make sure the hard drive was the only thing that went. I have been unable to boot any Mac OS Cd's. OS 8, OS 9.1, 9.2, OS X 10.3.7 etc. I can however boot debian (powerpc) and install with no issues. I also was able to install ubuntu (powerpc) with no problems. I tried hooking up an external DVD and even tried installing OS X from there but I get the same issue. The screen just goes back to the flashing question mark each time.

I have tested all of my CD's and DVD's in my mac mini and they work just fine to boot from, install, etc. Any ideas? Im new to old macs (if that makes sense) and IM ready to heave this thing out a window.

-Aaron

oh i have the same issue iv got a osx dvd and i cant get it to boot on a g3 its is a dvd drive in it i checked but yeah i cant get it to boot and os discs atm am i missing something