Tips
Problems with clicking is due to the drive having problems reading and usually it more serious that you expect.
The best thing to do is to switch off the Mac and do not turn it back on until you have contacted a Mac engineer.
This is usually a problem with the internal battery. There could be a more serious problem but the first thing to do is to check the battery.
There could be many reasons why you are getting this. It could be that the drive has lost it's headers and needs to be fixed or that the Mac can't see the drive for various reasons.
The best thing to do first is to Zap the PRAM, then try to start up via your start-up disks to see if you can see the internal drive. If that does not work, contact us.
Press and hold the [T] key while booting.
Press and hold the [Apple]+[ALT]+[P]+[R] while booting.
This will generally help with some minor problems, but I feel it's more of a placebo than anything major.
