"C:\Windows\System32\Autoexec.NT
The system file is not suitable for running MS-DOS and windows applications.
Choose 'Close' to terminate application",

There is a replacement copy of this file in the
C:Windows\repair folder. Copy this into the
C:Windows\System32 folder, then right click
on the file and select Properties, Make sure that
'Read only' is ticked and applied then click ok,
Then restart the computer.