Hello,

It is possible that you lost the hard disk... this is why backups are so important. Things like this can happen anytime anywhere -- on linux, on Mac, on Windoze.

Try booting from the CD-ROM with the OS disk that came with your computer. I am guessing it is OS X. You will be prompted to install... instead go to the upper left hand corner and click on the blue Apple. From there, select Disk Utility. Go into that program, and repair the hard drive. Check for permissions and also for general issues.

Restart without the CD. It should boot.

Christian

If repairing from the CD/fscking doesn't work, you can always try some disk repair software like DiskWarrior or TechToolPro. Do NOT use Drive 10. It sucks.

As noted above, this is one major reason you should get in the habit of backing up, even if you forget and do it infrequently, at least you have SOMETHING to fall back on.