16-bit Subsystem Autoexec.nt is not suitable for running applications.
You are getting an error from the 16-bit subsystem that an application is not suitable for running MS-DOS and Microsoft Windows applications.
There are 3 ways to fix this.
1.1 Navigate to c:\windows\repair
1.2 Right click on autoexec.nt and choose copy
1.3 Navigate to c:\windows\system32
1.4 Click Edit on the top and choose Paste
2. If that doesn't do it you can download a program that will automatically replace the corrupted system files for you from here:
3.If you don't have internet try the following:
3.1 Put the OS cd in the d: drive
3.2 Click Start, Run and execute cmd.
3.3 Type: cd \
3.4 Type: cd windows
3.5 Type: cd system32
3.6 Type: expand d:\i386\autoexec.nt_ autoexec.nt
3.7 Type: expand d:\i386\config.nt_ config.nt
3.8 Type: expand d:\i386\command.co_ command.com