Find the preferences file that you suspect is causing the problem and trash it. It is always a good idea to delete the Finder Preferences. The Mac has a battery inside that keeps the date and time and other settings current. If this battery fails all sorts of things can happen including no video. If the year has changed to 1956 it is a sure sign of a dead battery.
Outdated software can cause many different problems and conflicts.
Check with the software company or the version tracker web site for the most current version. If there is more than one copy of the System or Finder on your startup disk unexpected things can happen. If there is more than one copy of either, trash them from the non-active system folder. If an application runs short of memory allocated to it, the application may crash or not even load. You may want to increase the preferred memory setting.