A. Windows stores a last known good configuration which is replaced with the current configuration after a successful login.

If during boot the System hive is corrupt it will try to use the last known good, if this is also corrupt you will get the following error and NT will not be able to boot:

Windows NT could not start because the following file is missing or corrupt:
\%systemroot%\SYSTEM32\CONFIG\SYSTEMHardware Profile/Last Known Good menu

To resolve use one of the following:

Method 1

Use the emergency repair disk and choose the 'Inspect Registry Files' from the recovery menu. Choose 'Replace System Configuration' from the next menu screen. This will replace the damaged Registry hive with the one on the ERD however if the ERD is out-of-date you will lose any changes.

Method 2

If you don't have a ERD or its to old, restore the registry from a tape that has a backup of the registry (you would require a second parallel installation of NT).

Method 3

If you can't do either of the previous options the files that make up the ERD are stored on the local harddisk in %systemroot%\Repair directory. You can therefore manually expand this backup:

  1. Install a parallel copy of NT if you don't already have one
  2. Boot into this second installation
  3. Start a command prompt (CMD.EXE)
  4. Move to the repair directory of the ORIGINAL NT installation
    C:\> cd \winnt\repair
  5. Use the EXPAND command to expand the SYSTEM._ file
    C:\> expand system._ system
  6. Copy the expanded file to the main config directory of the ORIGINAL installation
    C:\> copy system c:\winnt\system32\config
  7. Try to reboot into the original installation

If it still fails uninstall NT and use Windows 98, you can play more games :-)