Monitor problems and Windows not restarting after sleep or hibernation mode are some of the most common reasons for computers displaying black screens while having power. Improper settings and hardware failures are also known to cause black screens.
Monitor problems causing black screens range from loose connection cables to complete monitor failures. Monitors typically have built-in power lights indicating the monitor is receiving power, and cables wear out over time causing them to become loose or defective. Hardware failure causing black screens requires replacement of the defective component to correct the problem. Faulty components are normally found by replacing them one-by-one with working components until the computer functions normally.