I have a slot-loading iMac (a friend's, "can you fix this project?") that was booting fine in os9.2, but the CD-r drive stopped working. In the process of troubleshoot, I booted in to 10.1 to find the problem. 10.1 seems not to have been loaded correctly, because all I get a screen asking me to pick an assistant from a list of (Ba-Dum Dum DUm) nothing. When I reboot holding option, I get only the choice of os X as though os 9 never existed. Is there a crazy key sequence that I am missing? I know the machine has os-9, because it booted there yesterday. Also, if I hook up an external cd-r drive, will I be able to boot from there? I already tried just by holding "c" and nothing happened. All help appreciated.

An external should do the trick. Run Disk First Aid from the OS X disk if you have it

Try this, boot into OS X. While starting up hold down the Command+S keys. You will be prompted to the terminal. Type in "/sbin/fsck -y" and hit return. Do not type in the quotes, leave a space inbetween the k and -, and all lowercase. This will do a systems check and repair anything that is wrong. If it does find errors run the same thing again until you have no errors. Then type in "reboot" (no quotes) and hit return to restart.

But how do I get it to boot from the external CDR? holding "C" didn't seem to do it. Maybe that's only to check the internal drive and not the firewire bus? I did run fsck and it found errors, and Iran it a second time and they were repaired, good tip there. Unfortunately, it doesn't seem to have fixed the problem. Here is a theory, is it possible that OSX was only ever half installed on this machine? What would that do? Anyone know?

For what it is worth, I figured out that starting norton in the external drive and holding option finds the bootable disk. Thanks everyone for the suggestions.