We have the same problem with my sons Macbook Pro, he deleted all the LaunchDaemon files on his Mac now all we get is the white screen with the grey apple logo with the spinning wheel. We have tried to boot from our Snow Leopard disc by holding down 'C', we can then hear the Mac trying to load the disc but eventually fails and ejects the disc and the white screen with grey logo reappears.
The Mac books original OS was 10.4.8 Tiger but we don't have the Discs.
Should the Mac load from the snow leopard disc? As it doesn't does that mean that there is a greater issue? Would the Mac boot from the original tiger discs? If we transferred the contents of the disc on to a USB device from another Mac would this be something we can boot from easier?
Your help would be greatly appreciated
I think the advice above should include one other thing
-first get another macbook, launch the problem one in target disk mode (hold T down and power on), then you can see it as a hard drive.
Back evrythinng up onto another external drive. At least you have all files. Time Machine obviously a better way to go here using frequently.
Secondly, try powering pon in Verbose mode (apple-v and power on)
you'll now see the problems - launch agents and daemons are skipped etc
This is actually where I'm at now. I have no optical drive working on the problem mac - how can I repair the problem one? (I deleted launch daemons and copied them back across)
I feel the problem might be fixable with repair permission (eg ls -l in terminal and chmod to change permissions)
or else a re-install method (from disk image or something?)