Solution or Workaround
After installing PC ARC/INFO and rebooting my machine, I get the following error message:
"Windows NT could not start because the following file is missing or corrupt: \system 32\ntoskrnl.exe
Please re-install a copy of the above file."
PC ARC doesn't install anything in the /winnt/system directory. It doesn't ever really touch the OS, just sets environment variables.
Repair the corrupt files by running a repair of Windows NT from the emergency repair disk.