jayzus the same thing has just happened me today. i have an old ibook g3 and a powerbook g4, and both got a bit of a shock at a gig i done last week. the ibook hasn't recovered yet but the powerbook came back for a bit and went etc etc.
so to cut to the point. i have been trying to target both comps to the my g5s (and others) in work to get my data off. it made the pb even worse, it wouldnt get past the startup screen. so i called apple with my acp and the standard checks didn't work. i was thinkin id have to send it back (again), but i gt the right info from the support site on apple.com
http://docs.info.apple.com/article.html?artnum=106214
so i had to do the sbin/fsck and it worked. well everything seemed to be fine so i copied a file onto the server and rebooted. for some reason i decided to target the pb back to the g5 and get the data off anyway, just in case. but when i did, the disk didn't come up on the desktop. then the pb would restart again. while i was doing all this i was searchin the web and i found this thread. joined up. and decided to do the whole sbin/fsck again.
im back to square one and now it freezes on the progress bars. and then it shuts down after login. the computer has just gone crazy (and so have i!)
dizzywizard
more to follow...