If you check wpi.cmd it checks for the wpi.ico file to find drive letter for cdrom see below REM Example, how to look for CDROM-drive. Must have a file to identify in its root (like WIN51 or WPI.ico). for %%i in (C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if exist %%i:\wpi.ico set CDROM=%%i: echo Found CD-Rom as drive %CDROM% Regards Colin Bate