Screen Display in Sleep Mode

[Udub]

My HP monitor is hooked to my MacBook Pro.  The monitor used to be black when the MacBook was in sleep mode.  Now the HP displays a "No Signal Detected" error message that roams around a black screen.  How do I permanently delete the roaming message and get the monitor back to being black while in sleep mode?

[mdklassen]

>  The HP displays a "No Signal Detected" error message that roams around a black screen.  

It's an "information" message -- the Apple computer has stopped sending video-output to it, and it reacts by reporting "no signal". 

Did you recently apply some updates to your Mac?

Somebody may have asked Apple to update their software to stop sending video-output signals.

> How do I permanently delete the roaming message and get the monitor back to being black while in sleep mode?

This is a question that you'll have to post on an Apple forum, unless there is an OSD ("On Screen Display") setup option within the HP monitor to go "dark" when there is no video-input signal.