LG LCD monitor goes in power saving mode

How old is your monitor? You may have some bad capacitors. At any rate, you'll have to take the monitor to a Technician for troubleshooting. Good luck.

Laptops often have a function key which switches from laptop only, external monitor only, laptop & external. One of the top number keys, along with the function (fn for short) must be pressed simultaneously to step through these.

Where these keys are at, may differ from laptop to laptop.

The monitor has failed, it is almost always cheaper to replace it than fix it.

More likely to have failed filter caps in the power supply just like 1751 as shown in my pictures. That will be the first thing to look for.
http://s807.photobucket.com/albums/yy352/budm/LG%20L1751S/
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net

i had the same problem.
connect the monitor with the analog cable and shut down your pc.
while it is off unplag the analog cable and place the digital one(dvi).
this should fix your problem m8 ;)

LG monitor shows a green light and then goes in power saving mode and a yellow light appears,

Try wiggling the Cord on the backside of the monitor.. Not the Power Plug Cord, The Other Cord that attaches to the PC. Do this once the monitor turns off , grab ahold of the cord about 2 inches from the back of the monitor, then bend the cord to the right, keep bending from the right to the left a couple times to see if your screen comes back, if it does, than you have a Loose connection and this sometimes causes the Symptoms you are receiving.. Hope it helps.

I think your monitor is unstable. Is it showing power saving when you boot your PC? Does it show something when the Windows XP splash appears?

I'd try this monitor on a spare computer. It sounds like the video card (motherboard integrated or otherwise)is not putting out any video information or missing sync signals. The monitor must receive these signals or it will go into standy/sleep mode. If the computer has integrated (on motherboard) video, check your bios settings to see if it is properly enabled. If it has a slot video board, then try a different video board. Your present board might be dead. Another possibility is a bad cable connection. check the connectors for bent pins. Assuming the connector is the standard HDB-15, it is easy to bend a pin over.

Your monitor goes to Power Saving Mode when the signal it is receiving is not correct. In all probability this is not a problem of the monitor itself, rather you should check the connections and the computer the monitor it's connected to. For example you could try a different RGB cable and try it in a different computer.