You must boot from the original Windows NT 3.1 Setup disks (or the CD-ROM) to access the repair menu. These are available on preservation sites like Internet Archive and WinWorldPC .
If you are trying to recover a legacy NT 3.1 installation, this guide covers how to obtain the necessary setup files and how to create or use a repair disk to restore your system. Can You Download a Windows NT 3.1 Emergency Repair Disk?
A record of all files installed and their checksums. windows nt 3.1 emergency repair disk download
Strictly speaking, you cannot download a pre-made ERD that will perfectly match your specific installation. However, you can download the required to initiate the repair process.
Compressed versions of SYSTEM , SOFTWARE , SECURITY , and SAM . You must boot from the original Windows NT 3
The ERD is a specially formatted floppy disk used in conjunction with Windows NT Setup to troubleshoot and repair a non-booting system. It is not a "boot disk" itself—it is a data disk used by the Setup program.
Windows NT 3.1 Emergency Repair Disk: A Legacy Guide While searching for a may seem like the fastest way to fix an old system, a "generic" download often won't work. The Emergency Repair Disk (ERD) is inherently machine-specific because it contains unique snapshots of your system's registry, hardware configuration, and installation logs. Can You Download a Windows NT 3
If your system is still running, you should create a fresh ERD immediately, especially before making hardware changes. Emergency Repair Disk - Windows Forum - TechRepublic