If you receive the subject message when checking the log settings, in Event Viewer, and possibly receive a log file full message, your registry's SYSTEM hive is probably corrupt.
Microsoft recommends restoring the SYSTEM hive or repairing the SYSTEM hive from an ERD.
This is fine if your backup or ERD are fairly current. If not, you may wish to try the following approach:
1. If you don't have the old ERD, type RDISK from a CMD prompt and press Create Repair Disk, them Exit. DO NOT press Update Repair Info. Label this ERD as old.
2. Run RDISK /S and lablel this ERD as new.
3. Boot the 3 setup floppies and choose to Repair the Registry only. Select only the SYSTEM hive. Use the old ERD.
NOTE: If you don't have the setup diskettes, run Winnt32 /OX or WinNT /OX from the CD-ROM. Don't forget to copy setupdd.sys from SP3 or SP4 to diskette 2.
4. Start Windows NT and verify that the subject error does not occur. If it does, you will have to use an older ERD or restore.
5. Use regedit and export HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\logfile.
6. Shutdown and repair the SYSTEM hive using the new ERD.
7. Start Windows NT, delete the key from step 5, and Import the .REG file from step 5.
8. Shutdown and restart.
9. Create a new ERD by running RDISK /S.
If this does not fix the problem, boot to an alternate install of Windows NT and use tip 182 to manually set the entries per the .REG file.