Always display 1280x1024 sometimes out of range

Change the settings on the PC by going to Control Panel and clicking on the display icon, then change the adaptor settings.

Well, it means that your display setting is not in match with your monitor's specs... Try to set it to defaults in display settings of the PC or reinstall display driver while in safe-mode.

This is not a GPO issue. The problem is that all Windows will attempt to set the new resolution and a fail-safe is that if you do not click the Keep Changes button after thirty seconds it switches back to the old settings. This ensures that if you set the resolution to a range the monitor or display adapter can't handle that you don't get 'stuck' with a blank screen.
Check that the display adapter in the Dell 780 can handle a resolution of 1280x1024 and that the monitor can also handle this resolution.

The resolution of the display is set higher than what your monitor can support. Boot into Safe Mode, Right click on display, Properties, Settings, at Screen resolutions select the default resolution of your monitor 1024x768 or 1280x1024, depending on the version . 

dude just check the bios first !
it the bios works then check the cpu adn the ram
it has to be one of these normally !

This is caused by a resolution and/or refresh frequency setting in your computer's display properties that exceeds the values supported by the monitor.
Find out the optimum (native) resolution of your monitor (in case of AMV 17V5 it will be 1280x1024 pixels), and supported refresh frequency (usually 60Hz for LCD monitors), and set your display properties to these values.

Your graphics card is set to a resolution of refresh rate that your monitor cannot handle, This can sometimes be one of the normal settings - there is not much you can do. Each monitor has a native resolution which the monitor should always be set at yours is:- 1280X1024

The laptop is widescreen at a guess. The external monitor is not. You need to change your laptop screen resolution to be something like 1280x1024, or, you need to tell the monitor to be a display EXTENSION not a mirror. Right click the desktop, properties, then Settings. Click on the 2nd screen, and set its resolution to 1024x768 or 1280x1024. It's here you would tell it to extend not mirror too.

Hello,

I don't know for sure because I don't own nor have I ever used one of these monitors before but this error likely means that either that there is a problem with the resolution or the frequency coming from the video card on your computer. The recommended resolution is 1280x1024@60Hz.

You can hook your PC up to your old monitor and check the Display Settings. According to the manual for the LG1780U (and many others) 640x480, 800x600, 1024x768 and 1280x1024 should all be acceptable values, although 1280X1024 will give you she sharpest image for this monitor.

If you still need help LG offers 24/7 tech support @ 1-800-243-0000.

I hope this helps!

Try lowering your refresh rate from 85hz (or higher) to a lower value around 70hz.
This usually will correct out of range issues.