You should have a display enable/disable switch in LMDE’s “Display” settings GUI, though it shouldn’t be necessary? Please try another (few) cable(s) because they do vary. Anecdote: I’ve heard of Samsungs being picky like this and only refusing to work with that one device you are trying to use.
Edit: Can your mouse pointer or windows get to the missing screen? Also xrandr -q
shows display status.
Taste of the boat?