We have a G5 mac from 2008 (?) that starts and has a normal desktop

[PJMcK]

1. A couple of thoughts

I hate to get rid of old computers when they (and the software) still work. But then the files can be difficult to transport to colleagues so the machine is only usable by me.

Anyway, do you have the original System CD's? I think you can boot the G5 using the CD: if you restart the machine with the CD in the drive while holding down the letter "C," the computer will use the System on the CD rather than the installed System to boot up. Do you know which Operating System you were running? Using the CD, you should be able to re-install the OS.

It's remotely possible that Apple still supports your OS. Try this Support page to search for any applicable updates:

http://www.apple.com/support/mac/

You can try calling Apple Support (1-800-MY-APPLE) but they're pretty sketchy. If you hard drive is finished, I don't know if you can get a replacement for such an old (!) computer. But, if you have a local authorized Apple repair center or Apple Store, they can tell you what options you have.

Good luck, marzipani.