a modern computer screen dark blanked and unresponsive troubleshooting hints possible causes

computer screen dark blanked shutdown malfunction fault frozen unresponsive inactive idle paused stalled halted stopped inoperable unlit darkened obscured shaded shadowed faint murky opaque screened curtained shrouded masked concealed blocked darksome somber dusky tenebrous umbrageous umbrous troubleshooting problems system issues display hardware software power outage error messages diagnostics technical support repair monitor issue digital blank empty black