Do you need to add a DOS driver or TSR into the autoexec.bat or config.sys file. The easiest way to do this is to open the file for "Append". If there is not already a file, it creates one, othewise, it adds the text to the end of the file:

Open "c:\autoexec.bat" For Append As #1
Print #1,mynewcommand
Close #1

This will add the text in mynewcommand to the end of the autoexec.bat file. New lines are automatically inserted after the end of each Print statement, so no need to add vbNewLine to each string.