Previously, the AUTOEXEC.BAT and CONFIG.SYS files—normally found in the root directory on your boot drive—were used to initialize the DOS environment. Today, the venerable AUTOEXEC.BAT file is replaced by AUTOEXEC.NT and the CONFIG.SYS file by a new configuration file CONFIG.NT, both of which are located in your \Windows\system32 directory. Unless a different pair of startup files are specified in an application's .PIF (Program Information File), the AUTOEXEC.NT and CONFIG.NT files will be used to initialize the MS-DOS environment.
When a DOS program is executed by clicking on the application's .PIF icon, the pif settings take effect and control the application's DOS environment. If, however, a DOS ...