Help: Cannot startup, not even with system discs

Question

My MacBook (Intel, 10.4.11, no peripherals attached) cannot startup.
If I press the power button (either without pressing any other key, or press and hold 'shift', 'command-v', or 'command-s'):
- there is a regular startup chime
- a blank grey screen shows
- I hear repeating faint clicks from inside the MacBook
- no further progress from there on (waited 10 minutes)
If I press power button and quickly insert the Mac OS X system disc (either without pressing any other key, or press and hold 'c', or 'd'):
- there is a regular startup chime
- the disc spins up
- a grey screen shows a blinking file folder with a question mark
- no further progress from there on (waited 3 minutes)
I have tried the following without success:
- make sure RAM and hard drive are properly seated by taking them out and putting them in again.
- reset SMC
The last thing I was doing before this problem:
- I left the MacBook while it was burning a data DVD using Toast
- When I came back 2 hours later, the bottom part of screen shows a gear wheel spinning. I also saw a progress bar with Toast. I cannot eject the DVD or get any response by pressing any key including force quit keys.
- I pressed the power button to force shut down.
- I pressed the power button to start up. I held the trackpad button and the DVD ejected but did not start up from there on.
- I cannot start up the MacBook since then.

Answer 1

The HD is so messed up that it messes with normal booting.
Your best bet other than Apple Service is to disconnect the HD ribbon cable, insert the Install disk, hold Option key down on startup, select DVD to boot from, after it boots, recoonect the ribbon cable to the HD, then "Try Disk Utility
1. Insert the Mac OS X Install disc that came with your computer, then restart the computer while holding the C key.
2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu. (In Mac OS X 10.4 or later, you must select your language first.)
Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.
3. Click the First Aid tab.
4. Click the disclosure triangle to the left of the hard drive icon to display the names of your hard disk volumes and partitions.
5. Select your Mac OS X volume.
6. Click Repair. Disk Utility checks and repairs the disk."
http://docs.info.apple.com/article.html?artnum=106214