External monitor enters power save mode

I have a Dell M6400 laptop and an external Dell 24" monitor. When I connect my Dell M6400 laptop laptop to a DELL monitor, initially the Dell will show the "Resuming Windows" but then immediately goes into "Power Save Mode". Whenever i try to open the monitor, i keep getting the message Entering power save mode, press Pc button or any key, but it doesn't work. Can any body tell me that why does my external monitor enters in to power save mode? How do i turn power save mode off? Does any body knows about it? Kindly help me out to resolve the above issue.

I think you should check out your VGA cable, it might be loose. Check your power settings. You need to press the Fn key and CRT/LCD key found in the F keys to switch the screen. After that try to open up your computer and reseat the RAM.

This could realted to power distribution on the board as well. Turn off and unplug your computer, take each card (PCI, AGP, PCI Express, Etc.) and reseat them. Try to remove the video card, if present to eliminate the cause. In Bios, change the sleep settings to S3. This can clear the issue most of the time, if not you might have a conflict between hardware devices, repeat the process, removing the cards again, but this time go it one at a time with a "boot" in between to narrow down the issue.

Most laptops have the option to setup a second display by "Extending the Desktop" or "Mirroring" the laptop screen with the external monitor. It still appears as if you haven't done that. Unplug the computer from the wall. Hold the power button for 10 seconds or so. plug the computer back on. Turn it on again. It worked for me, hope it works for you. Make sure you've also selected "Use this device as the primary monitor" when you've highlighted the #1 monitor listed in the display "Settings" tab. UNCHECK it when you've highlighted the #2 monitor.