16 bit windows subsytem

The last couple of weeks when my computer has booted up I get this window/message.

16 bit windows subsystem

C:\WINDOWS\SYSTEM 32\AUTOEXEC.NT.
The system file is not suitable for running MS-DOS or Microsoft applications.
Close................Ignore.

Now when I try to use cd's this same message comes up every time.
Can anyone help me with this problem.

http://support.microsoft.com/default...b;en-us;324767