Dual 1.8 G5 won't boot from a CD or DVD

This is odd... I recently bought a used dual 1.8Ghz G5 off of eBay. I
installed the new version of Tech Tools and found that one of the hard
drives has a bad sector on it. No big deal, I'll just install Tiger on
the other empty hard drive, make an image of the primary hard drive,
wipe it clean, then reinstall the image onto the repaired drive right?
Well I can't get it to boot from my Tiger CD now! I've tried double
clicking on the installer icon, which should automatically make the
computer restart and boot from the CD, except that when it reboots,
it's still booting fromt the hard drive. Then I tried manually going
in and setting my startup disk to the OS found on the CD. That had the
same results, still booting from the hard drive. Then I tried
restarting and holding down the C key... Same thing, booting from the
hard drive. So then I tried to boot from an old Panther CD that I know
should work because I used to use it on my previous G3 computer. This
time it acted like it was booting from the CD but halfway into boot up,
the screen went gray (the screen with the gray apple in the middle and
the little spinning wheel underneath), and told me that my computer had
a problem and I needed to restart it by holding down the power button
for a few seconds and then pressing it again. So this is where I'm at
with it now. I'm at work now but tonight I was thinking of trying to
mess with the master/slave settings on the DVD drive. I'm new to a G5
but I remember having similar difficulties with those settings on my
old G3. That's really the only thing I can think of right now. I've
run disk utility and tech tools to try and repair anything wrong with
the startup disk but it's saying everything is fine now. The firmware
is up to date as well... Any thoughts would be appreciated!!

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