Pavilion 27xi Monitor sleep problem

[ESJONES]

I have a HP Pavilion 27xi monitor, which behaved perfectly when I was running Windows 7 Pro, but is giving me problems since upgrading the PC to Windows 10 Pro.

The issue is that when the system puts the monitor into sleep mode (I have it set for 30 minutes of inactivity) the monitor does indeed go blank, but shows the alert “Monitor Going to Sleep” repeatedly on and off throughout the time the monitor just should be blank (off). It's as if the monitor goes to sleep only to wake a few seconds later to say it's going to sleep again, and on and on and on.

This did not happen under Windows 7. The monitor would blank when the system went into monitor sleep mode and stay blank until there was mouse or keyboard activity.

How can I diagnose this issue and fix it? Windows says the installed monitor driver is the “best” for my monitor.

FWIW, the system is HP ProDesk 400 G3. The system has a Display Port output, and I am using the same Display Port to HDMI adapter that I used with Windows 7.

[ESJONES]

If the monitor is set to sleep OR is powered off, the system goes to sleep after a time. If the monitor is left on and set to never sleep, the system remains active. What I want is for the monitor  to be able to sleep while the system does NOT sleep.