An office employee reports that their computer suddenly displays nothing but a black screen, although the power LED on the monitor and system unit are on. You observe that the monitor status light is indicating a connection, and you hear the computer's fans running. What is the FIRST step you should perform in troubleshooting this problem?
Replace the computer's power supply unit (PSU) as it may not be delivering enough power to the video card.
Replace the video card with a known good one to see if the display returns.
Check if the video cable connection is secure between the monitor and the PC.
Reboot the system to see if the display returns after a restart.