You are giving a talk in 5 min. You attach your Kubuntu 14.04 LTS "Trusty Thar" laptop to the beamer. The laptop screen goes black for a second ... reappears ... and ... nothing. The beamer reports "no input". No message on your screen. 4min to go. Panic.
Keep cool. Do not reboot. Do not turn off the beamer. Both take too long and never fixed anything for me that was not fixed otherwise. Try the quick things first:
Emergency Routine 1
- Press ALT+F2 (This opens the KDE quick starter. If not on KDE, open some other terminal input window.)
- Type xrandr --auto and press return.

