I woke my Macbook from sleep and immediatly I get a Kernal Panic. I Quickly Restart and the computer does not startup. It stops at the grey/white screen that first appears, (no apple logo), then three clicks are heard; waiting a min or so the clicks repeat again. The computer is unresponsive. I have not installed any software resently and am running Mac OS 10.5.2. What should I do? It has run perfect up un till this point.
Kernel Panics can be caused due to a hardware problem. The clicking is most likely coming from you hard drive, and it would probably be best to have it replaced since HDs that have one problem will continue to have problems.
If you still have Apple Care, just take it in to get serviced since they will replace the drive for free. If you want to get your files off the Mac you will need to either take the drive out and hook it up to another Mac, or set your current Mac into Target mode and connect it to another Mac with a firewire cable. If there is an Apple store near by, go there and have them help you get you files using Target mode if you don't have a second Mac, and have them send it in for servicing if you have Apple Care.
If you don't care to get the files off it, but want to see if you can resurrect the drive and not send it in for servicing, then break out your OSX disk and boot to it. Then use Disk Utility from the menu and see if you can Verify and Repair the drive. If it boots after that then you might be good. If not, you can try and Archive install but your drive might be damaged so you might end up with the grey screen again. Another thing you can do is to Initialize the drive and reinstall OSX from scratch which means loosing everything.
I personally had a grey screen recently and had to ReInitialize my drive to get it to work, but since I use my iDisk I didn't loose anything.
But if you are covered under Apple Care and have a Apple store near by, just take it in for some help. Otherwise call Apple tech support and they will get the drive replaced. Moral of the story, keep backups of your files.