NO_DIALOGS=N - set to Y to make the install as silent as possible
SHOW_SAMPLE=N - Changes the default for showing the sample movie. If NO_DIALOGS is yes, then SHOW_SAMPLE defaults to no.
SHOW_README=N - Changes the default for showing the README file. If NO_DIALOGS is yes, then SHOW_README defaults to no.
SHOW_PROGRAMFOLDER=N - Changes the default for showing the program folder at the end of the install. If NO_DIALOGS is yes, then SHOW_PROGRAMFOLDER defaults to no.