Error Message :
16 Bit Windows Subsystem
C: WINNT\system32\AUTOEXEC.NT. The system file is not suitable for running MS-DOS and miscrosoft windows applications. Choose 'close' to terminate the application.
This issue can occur if any one of the following files are missing, damaged, or not located in the c:\ WINNT\System32 folder:
For Windows 2000 Pro Browse to C:\WINNT\repair
For Windows XP Browse to C:\WINDOWS\repair
Right-click and copy the file named autoexec.nt
For Windows 2000 Browse to C:\WINNT\system32
For Windows XP Browse to C:\WINDOWS\system32
Right-click in that folder to paste the file.
Now do the same with config.nt
The problem is the autoexec.nt and config.nt gets corrupted. You need to replace it with the new one. Your program should load then.
Windows XP Professional - 32 bit re 16 bit errors
You may need to be logged in as administrator. No version of windows NT supports 16-bit programs that require unrestricted access to hardware. If your program requires such access, your program will not work in Windows XP, or any other version of NT. Note that if the 16 bit program requires a virtual device driver (VxD), it will not work properly under Windows XP.
Windows XP Professional x64 Edition Windows XP Professional x64 Edition
When moving to Windows XP Professional x64 Edition, you need to understand some key differences. The most important is that there is no support for legacy MS-DOS and 16-bit applications. If you have an older application that runs in MS-DOS mode or is a 16-bit application, you shouldn't move to Windows XP Professional x64 Edition until you can either update or replace the application. Some 32-bit applications have 16-bit installation programs. Many of these will not install on Windows XP Professional x64 Edition, since 16-bit applications are not supported.
Applications that install their own hardware drivers will not work until there is a 64-bit driver available for them. Windows XP Professional x64 Edition doesn't support 32-bit drivers at all. All drivers must be 64-bit. There are three main reasons for software incompatibility on x64, according to Microsoft. First, some applications are still using old-fashioned 16-bit installers, even though the applications themselves are 32-bit; since XP x64 doesn't support 16-bit applications, you can't install them on that system.