Macbook will not boot cd

I recently acquired my friends macbook to try to repair it since it would not boot. It would boot and show the flashing question mark folder. I tried booting while holding shift and that did not work. I also tried using disk utility to repair the drive which it could not. After that I ended up trying diskwarrior and left it running for a day and a half and then eventually quit that. My main problem now is that I can not even boot from the mac install dvd to reinstall. I have tried holding down c but that does nothing. I have also tried holding down the option key and it just brings up a screen with a cursor and no options to boot from. Before I ran diskwarrior I was able to see both the harddrive and the cd that was in. Any ideas on what could be going wrong? Thanks for all the help in advance.

I would recommend using the Option key startup only (and be sure to press and hold immediately after turning the machine on). That forces the EFI to scan for bootable devices, including optical media. I've had limited success using the 'C' key for some reason.

If it still shows no bootable devices, do you have an external USB DVD drive available to you? It sounds like the internal drive might just be having trouble reading those discs. In my experience the slot-loading drives they use in portable Macs are particularly finicky.

Holding the option key still just brings up a grey screen with a cursor and no bootable options. I have tried booting other cds but they will not boot. I know the drive still works because I was able to boot the hardware test by holding the d key while the mac install disc was in. I don't have access to an external dvd drive either unfortunaley. Any idea on how I can get the cd boot to work?

Sounds like it s time for a new drive if DiskWarrior and Disk Utility can do nothing with it.

Okay I ended up pulling out the harddrive and the dvd drive is able to boot perfectly fine now. I'm just curious if a bad harddrive could cause the dvd drive to not be able to boot?