Lets users run a 16-bit program in a dedicated (not shared) Virtual DOS Machine (VDM) process. All DOS and 16-bit programs run on Windows 2000 Professional and Windows XP Professional in the Windows Virtual DOS Machine program. VDM simulates a 16-bit environment complete with the DLLs required by 16-bit programs. By default all 16-bit programs run as threads in a single shared VDM process. As such they share the memory space allocated to the VDM process and cannot run simultaneously. Enabling this setting adds a check box to the Run dialog box giving users the option of running a 16-bit program in its own dedicated NTVDM process. The additional check box is enabled only when a user enters a 16-bit program in the Run dialog box.