Torrent bound

Hi there!
Have you tried any keyboard commands on startup; the most basic and
first would be to see about getting the machine to start in SafeBoot mode.
This is done by holding the Shift key on startup just after the boot tone is
heard and then keep holding that key down until you finally get a dialog
box that says it is starting in SafeBoot. In OSX 10.3.x, this is an easy
window; if you have 10.4.x that SafeBoot window would have a login box.
If you can get the computer to start and run in SafeBoot, you can see if
you can use Disk Utility's 'Repair Disk Permissions' and maybe check
other aspects of the computer. Normally, you'd not run the computer
under SafeBoot; just use it to troubleshoot and try to repair it. The Mac
would be restarted to see if anything was corrected; since SafeBoot does
check and try a few repairs while you are starting in it. That is part of the
reason why it takes time to get it running in SafeBoot.
Another idea is to get the OSX installer disc#1 and get the computer to
boot from that disc's system by holding down the C key on startup until
the disc's Installer loads. You use items in the drop down menu below
the Installer's name in the header, such as Disk Utility; and you can
see if a 'repair disk' sequence, used at least twice, may find and try
to fix any basic errors in the computer's startup system on the drive.
You can also 'repair disk permissions' from the booted installer. And if
you find errors it fixed in 'repair disk' run it again to get a good report
before Quiting Disk Utility. You choose to restart from the Mac's HDD
from the startup disk selection beneath the Installer's menubar name.
You can also use the Installer to do an 'archive and install' of a new
system folder; and there should be an option checkbox to have it save
your system preferences and user account into the new installation.
The older system would be saved as a non-bootable previous system.
Hope this helps. If the hard drive has a physical defect or a defect in
the startup software on it due to other issues (a full hard drive will start
to cannabalize data onboard and this overwriting may kill a hard drive)
you may be faced with other tech repairs. Data recovery is the hardest
one due to costs involved; but if you do need a new hard disk drive, the
old one can sometimes be put into an external enclosure and other disk
tools can be tried later to see if you can get data off the disc. Some
non-bootable disk drives can still be seen by using another computer
(a Mac) with FireWire ports and a cable, and using Target Disk Mode to
get what you can off the non-bootable hard drive prior to taking it out.
And sometimes, third-party disk utilities, such as Drive Genius, Disk
Warrior and others (avoid Norton/Symantec) may do a repair on a HDD.
This may help get it going again, but if the drive is failing, you need to
look into getting it replaced. There are good options in new drives.
Hope this helps; good luck!