How Windows NT Uses MS-DOS Configuration Files

During system startup, Windows NT adds any Path, Prompt, and Set commands from the C:\Autoexec.bat file to the Windows NT environment variables and then ignores the rest of the contents of C:\Autoexec.bat and C:\Config.sys. If these files are not present when you install Windows NT, the Setup program creates them. Setup also creates default Autoexec.nt and Config.nt files.

The path and other Windows NT environment information are stored under the following Registry key:

HKEY_LOCAL_MACHINE\System
\CurrentControlSet
\Control
\Session Manager
\Environment

When an MS-DOS-based application is started, Windows NT executes files specified in the application's program information file (PIF) or the Autoexec.nt and Config.nt files in the Systemroot\System32 directory. Any changes made in one of these files take effect as soon as the file is saved and a new MS-DOS-based application is started that uses that file. You do not need to restart your system after changing the .nt files. Windows NT uses these files as follows:

Files	Use in Windows NT

C:\Autoexec.bat	Path and environment variables are added to the Windows NT environment at system startup.
C:\Config.sys	Not used by Windows NT.
Autoexec.nt and Config.nt in Systemroot\System32	Used every time an MS-DOS-based application is run with _Default.pif. (Custom .nt files can be created and used when starting an application from another PIF.)

You can use any text editor to view the contents of the Autoexec.nt and Config.nt files.

Commands in the Autoexec.bat and Config.sys files for starting applications and initializing drivers are ignored in Windows NT.

To run an application automatically when you start Windows NT, use the Taskbar option on the Start menu to place a shortcut to the application in the Taskbar Startup group. For more information, see Windows NT Start Here.
To run a service or driver automatically, use the Services option in Control Panel: In Control Panel, double-click Services. Select a service from the list, then click the Startup button. In the Startup type field of the Service dialog box, click Automatic, then click OK. This setting is saved as the Start value in the service's subkey under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services in the Registry.