warning HP

Error Code Continuous beeps or single beep

Computer not responding after power button press, could indicate software control failure.

? What Causes This

Software malfunction, causing improper handling of shutdown signals from hardware switch input.

How to Fix It

1. Hold the power button for 4 seconds to force system shutdown before unplugging cord.

Source: page 73 of the official manual

From the manual

Manual page 73 — HP error Continuous beeps or single beep

This error code appears in:

HP Prodesk 400 G3 Desktop Mini PC