Ati HD 5850 not sleeping monitor

Hi all,

I'm having some issue with my monitor deciding not to sleep. The system will sleep correctly, but as soon as it does, the monitor begins displaying "Check Signal Cable."

What's interesting is that the problem cropped up randomly, leading me to believe a Windows Update is responsible. I've been using the same copy of Windows 7 Ultimate 64-bit, the same HP w2408h monitor, and the same set of Logitech wireless mouse/keyboard, and it used to have no issues powering down the monitor when the computer shut off.

If the computer is running, the monitor sleeps correctly (using the 5 min timer through the Windows power management); it's only when the computer itself sleeps or turns off that the monitor refuses to power down.

I've already turned off hibernate using the powercfg command in the elevated command prompt: same issue.

Anyone have any suggestions or had a similiar problem?

I'm using the most recent Catalyst Drivers (9.12) and I don't recall which update could have done it...I have them set to automatic and I didn't really notice it as a problem until a few weeks ago.

What's so strange about it to me is that while the computer is on, the monitor sleeps perfectly. Then, the instant the fans/leds power down when the computer sleeps, the monitor turns back *on* and says "Check Signal Cable."

It's a boggle.