LG Monitor goes into HDMI Power Saving Mode

Hi,
I have an LG Flatron monitor that I only use to view DVDs with via the HDMI cable, an HD DVD player & stereo.

It has worked beautifully for about a year. I think my daughter might have done something or pressed something because now the screen automatically goes into "HDMI power saving mode" no matter what. I've tried hooking the monitor up to my computer with the RGB cable and it works fine...

Any ideas?
THANKS!