Corrupted OS, please help!

So I'm running (or was) a mac book with OS X 10.4.x
About two weeks ago I turned it on and all it showed after making the apple sound was an image of a file with a question mark in the middle flashing over the basic blue background.

I went to the apple store and they told me that the OS was corrupted and that basically I could pay an arm and a leg for Leopard or I could put it in the trash.

None of my friends have macs but I can borrow a PC from school.

Now that I'm done whining I'll get to my point:
Is there any way I could fix the computer without buying a new OS (seeing as this is literally impossible on my budget)?

Thanks guys.

So this is probably an older White Macbook with 10.4 Tiger?

Ok, firstly do you have the OSX DVD that came with your Macbook? If you do, you do not need to purchase Leopard at all. Put in the DVD and hold down the C key. When you get to the Tiger Installer, go to the tools menu up top and look for Disk Utility. Run that and see if the Hard Drive shows up and if so try a repair.

This is just a guess but I have a feeling your Hard Drive went Belly Up! A lot of the older Macbooks used the same Seagate drive and many had issues and failed. When you are in the Disk Utility, if the drive shows up look at the bottom for S.M.A.R.T and see if it says Passed or Failed. If it says Failed your drive is dead.

Also you can boot into the Apple Hardware Test and test the Hard Drive and all the other hardware. Power on with the DVD in the drive and hold the D key till the hardware test starts loading.

If the drive is fine in the tests, hold down C after the startup sound and boot into the OSX installer and reinstall. Keep us posted.

sorry, I forgot to mention that the OSX DVD is long gone and far from readable.

oh and the drive is fine (unless they lied at the store)
thanks again.

That's a shame. Your System Discs are important - not only do they have diagnostic tools so that you could verify that the HDD is good, but they also have the iLife suite, that you'll be missing even if you bought Leopard and did a clean install.

In my experience, it's exceedingly rare that a OS X would spontaneously become corrupted, to the point that you can't even boot it in safe mode. It's more likely that the HDD has an issue.

My recommendation would be to call Apple Care and see if you can purchase a set of system restore discs, or hit up eBay for a set - particularly if you're not interested in upgrading to Leopard.