When you attempt to run or install a MS-DOS or 16-bit Windows program on Windows XP, you receive a message similar to any of the following:

16-bit MS-DOS Subsystem - path to the program that you are trying to start or install C:\Winnt\System32\config.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.

16-bit MS-DOS Subsystem - path to the program that you are trying to start or install config.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.

16-bit MS-DOS Subsystem - path to the program that you are trying to start or install C:\Windows\System32\Autoexec.nt The system file is not suitable for running MS-DOS and Microsoft Windows applications. Choose 'Close' to terminate the application.

Regardless of the option you choose, the program exits.

To resolve these issues, see How do I troubleshoot MS-DOS programs running on Windows XP?