Upgrading From 10.3.9 to Tiger On G4 533mhz Won't Reboot


I've Upgraded from 10.3.9 to Tiger on g4 533MHz and computer won't reboot. The startup drive for the Tiger OS is a 40 gig partition of a Maxtor 160 gig second internal drive. Do I have any recourse? I didn't back up. Don't want to reinstall if I don't have to.

I've come across Disk Warrior on the Web. Will this fix it?

Can I somehow access the drive to move a few files, if a new install is necessary?