16-bit support was dropped with Vista. DosBox is an alternative, but only if the game is native DOS.
The lack of 16-bit support is one reason why Vista/7 have and will do so badly in the business market; I know that at the place I work (a major software company), we still operate between our sites on a 16-bit telnet connection, which won't work on Vista/7. Hence, we use XP/2000.