Most 16-bit and MS-DOS based programs runs as a thread within virtual machine in Windows 7. Since all these 16–bit and MS-DOS programs run on a single thread in Windows 7  and they share single memory space ,there is a chance  if one program hangs or crashes then it crashes other programs as well specially when you are running multiple 16-bit programs.

This can be avoided by running each 16-bit/MD-DOS program in a separate memory space.

To run 16-bit and MS-DOS  applications in a separate memory space in Windows 7

1.Right click on the application shortcut (create shortcut for that application , if it does not exist) .

2.Click Properties, click Advanced and select run in separate memory space.

run in separate memory space

3.Click Ok twice  to save changes and close all dialog boxes.