You may have a completely blown OS. Last chance? See if DDU (see google) runs in safe mode to remove ALL graphic drivers to force Windows to use a default one.
Using a borrowed screen..when booting my dell optiplex780 i get just as far as the windows start then get black screen and red outlined 'out of range' box. .. so far i've..
1. botted in safe mode .all ok. I can go to up 1240x1080 ok
set res to 800x600 .. normal boot ..same error
2. freqency is giving 'Use Hardware default settings' only option
3. uninstall 2 identical display drivers. both
INTEL(R) Q45/Q43 express chipset (Microsoft Corp - WDDM1.1)
normal boot goes ok except i get 2 display drivers again and 1 is yellow
warned. I get' you need to restart for these changes' if i do it goes 'out of range again. so i don't restart then.. screen is ok but...directx is really broken ... none of the three parts are found.
4. dxwebsetup run. just tells me directx is ok. Can't figure out how to replace directx11 .
5. so in safe mode the monitor has 1 driver .. all fine. In normal mode it has 2 with one sick. I read similarish mails and tried all suggestions there.. heeeelp