The COMMAND.COM in Windows NT is used with 16bit applications.

COMMAND.COM is located in the %SystemRoot%\System32 folder.

If you receive:

wowexec
config.nt. The system file is not suitable for running DOS and WINDOWS applications. Choose 'Close' to terminate the application.

you replaced COMMAND.COM with a version from MS-DOS 3.x, 4.x, or 6.x.

If you receive:

wowexec
An application has attempted to directly access the hard disk, which cannot be supported. This may cause the application to function incorrectly. Choose 'Close' to terminate the application.

you replaced COMMAND.COM with a version from MS-DOS 5.x.

To resolve the problem:

EXPAND \I386\COMMAND.CO_ %SystemRoot%\System32\COMMAND.COM