Wont go into standby

Hi

My Flatron WS22 LG monitor will often not go into power save mode when Windows shuts down.

The power button remains blue instead of yellow meaning that once Windows has shut down the monitor is still on but with no display being received. When I restart Windows the display remains black forcing me to press the monitor's power button off and then on again to get the display back up.

I have a triple boot 2 x XP and 1 x Win 7 and this behaviour occurs in all 3 OSs. I have 2 monitors hooked up to my PC and the smaller Dell LCD monitor works fine regarding going into power save mode.

Sometimes however the monitor will work as its supposed to and had been working fine until recently.

Any ideas?

Cheers