This morning we lost power and my iMac G5 (10.4) system got messed up. Specifically, when it restarted, all text in all Finder and application menus were blank (e.g. Click the Apple menu and a long empty white box stretching to the bottom of the screen would appear with no text. The whole box turns blue when you click in it. Ditto for all other finder menus and dialog boxes. Event the User menu was empty. The Disk Utility application shows only icons and empty buttons--no text.)
Restarting in Safe Mode was no better.
I then connected the G5 as a target disk to my iMac G4, and ran the OS X install that came with the G5 (10.3.2). It told me that in order to install an earlier OS X version, I must select certain options: I checked "Archive and Install" and "Preserve Users and Network Settings" (I have 4 accounts set up in addition to my onw admin account) and proceeded with the installation.
At the end of installation, the G4 started (G5 is still in target disk mode) with the G5 as the startup disk. It presented the User Login screen (although it normally does auto-login on my account) but the password for each of the 5 accounts was rejected. The original hints still appear, but it seems that all passwords have been changed.
I then tried the G5 on its own (not as a Target disk) but when it starts up the grey Apple turns into a grey "do not enter" (circle/slash) icon and goes no further.
Can you suggest what I should do now?
iMac G5 2.0GHz Mac OS X (10.4.7)