screen:
Right Click on the shortcut to the dos window you use - or, if you've associated a program with the shortcut, that shortcut, then properties->layout, and adjust the screen buffer size - as you want it...
for autoexec.bat commands:
right click on my computer->properties->advanced->environment variables.
For config.sys settings - find and modify config.nt file - 10:1 under \windows\System32...
That should do it...