Mo's Computer says System32/Config/Software is either missing, corrupt or has an error.
"A Repair Install is not foolproof and should not be considered the cure-all fix for non-boot situations." says an XP Repair FAQ. This is true.
If you've got a spot on your carpet, should you rip up the floor and lay new carpet?
I updated the wife's computer's network drivers yesterday and got this lovely error on reboot:
Blah blah Systemroot/system32/config/Software is either missing, corrupt or has an error.
You'd think they'd know if it were missing or not. ;) I thought seriously about doing reinstall/repair install, but then thought there might be a simpler, less drastic solution.
I held down F8 and tried "Last Known Good Configuration" and that didn't work. I also couldn't get into the system via Safe Mode, but I could get into the Recovery Console. The Last Known Good and Safe Mode not working (via my gut) told me that there was probably a disk corruption error around the area of the registry file, rather than a corrupt hive.
From within the console I changed directories down to system32/config and saw that SOFTWARE (the Registry Hive) was in fact there, and was of a reasonable size for this simple machine (about 26 megs). I ran chkdsk /p (it's /p, not /f, inside the Recovery Console) and it found and fixed errors. Rebooted and was were back in business.
(Had this not worked, the next step would have been a purchase of ERD Commander)