Diagnosis
The monitor is receiving power and is in an 'on' state, but the LCD panel or backlight is not activating. This can indicate a failed internal component or a deep sleep state.
How to Fix It
1. Perform a hard reset. Unplug the monitor's power cable from both the wall and the monitor for 5 full minutes.
2. While unplugged, press and hold the physical power button on the monitor for 30 seconds to drain residual power.
3. Reconnect only the power cable directly to a wall outlet. Do not connect the video cable yet.
4. Press the power button. The HP logo should appear on a black screen indicating 'No Signal'. If it does, the monitor is functional.
If That Didn't Work
Test with a different, known-good power cable and outlet. If the white light still comes on but the screen remains black with no logo, the internal power board or backlight inverter has likely failed. This requires professional repair.
Heads Up
A very dim image visible only with a flashlight indicates a backlight failure. A completely blank screen with a white power LED suggests a main board or panel failure. This model does not have user-serviceable internal components.