SP4 adds a 10 second countdown timer to Autochk, the process that runs Chkdsk on the blue screen during boot.

You can alter the default timer value by navigating to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager

Add Value name of AutoChkTimeOut as a type REG_DWORD. Select the Decimal Radix and enter the number of seconds desired.

If you set the value to 1, it will effectively cancel your ability to abort the Chkdsk.

Bug: When you schedule a chkdsk on NT 4.0 SP4, the system event log records Event Id 41, The file system structure on the disk is corrupt and unuseable. Please run the chkdsk utility on the device \Device\Harddiskx\Partitiony with label "z". where x, y and z match the drive letter you scheduled. On my Server, I get an Event ID 41, description not found.