iMac, won't recognize repair disc

I'm currently running.
10.5.8
2.66 intel core 2

I ran repair permissions & it gave me a warning that volumes need to be repaired, run start up disc. I proceeded to do so but when I try the "Holding down C" key it doesn't work. My iMac just takes me right to the login screen.

I've tried "Startup Disc" in system preferences but there's no choice to boot from DVD drive as suggested by others. When reading some of the repair permissions findings I'm noticing about 5-6 plist issue's, not sure what that is. The only issue I'm seeing that started about the same time is my sending mail on mac mail is pretty slow, takes about 10 seconds before send is complete & some DVD's & CD's act like they want to eject but then doesn't & reloads again.

Is my hard disc already going out?

I'd say your optical drive may be starting to go, not your hard drive.

Interesting? So is there a program I can use out there that I can run that will do the same thing as running the install disc? I thought this free program I downloaded called Applejack was the ticket but it didn't do anything, well I can't say that it still ran completely through the utilities process & it appears to have repaired permissions, maybe? What about deleting my plist for mail since it's running slow to send? Can I give that a try or will deleting the mail plist cause more problems?

Stretch said:

I'd say your optical drive may be starting to go, not your hard drive.

Click to expand...

Take a can of air and shoot 2-3 quick bursts into the slot in different directions - while the machine is powered down of course and wait 30 seconds to turn it back on.

Then hold down the option key instead of the C key until you get the boot menu.

You may have quite a number of permissions that will not be repaired - this is totally normal and Apple has a long list of the ones to ignore.

Just a thought! Are you holding the "C" key continuously? It can take quite a time to start loading from the disc.