OS X kernel panic and other problems: Need to erase disk?

Kenneth Marcus writes that, after installing iTunes and OS X 10.0.2 updates, he got a kernel panic upon launching iTunes (note: this is likely a rare problem; we have had no other reports of it). Even worse, on restart, 90% of the icons in OS X were now nonfunctioning (he got the OS X equivalent of "application not found"). He adds:

"DiskWarrior 2.1 told me about 140 files had overlapped, mostly 'temp12355' and the like but including a file called 'mach.sym' (as I recall). However, the problem persisted after restarting again in OS X. I tried reinstalling 10.0.0 from the CD - but the problem remained. The only thing that worked was erasing the disk and starting over. But this meant that I lost all the customization and added software that had not been backed up. Is there something other than erasing the disk that I could have done to solve this?"

Good question. Any answers?