This question has been asked many times here and in other forums. I tried everything I could find, nothing works.I'm trying to use my NVIDIA GT540M on Ubuntu instead of Intel Graphics, but I have two screens: my laptop screen and a external monitor (HDMI).If I uninstall the nvidia drivers, the external monitor works again (because Intel is being used).When I install the drivers to use the nvidia card, the external monitor doesn't work. Nvidia X Server Settings doesn't recognize it and neither Ubuntu settings. If I set Intel Graphics on Nvidia X Server Settings, the external monitor doesn't work too. The only way it works is if I uninstall the driver completely.I'm using the 367.57 driver.xrandr outputScreen 0: minimum 8 x 8, current 1366 x 768, maximum 16384 x 16384LVDS-1-1 connected primary 1366x768+0+0 344mm x 194mm   1366x768      60.06*+   1360x768      59.80    59.96     1024x768      60.04    60.00     960x720       60.00     928x696       60.05     896x672       60.01     960x600       60.00     960x540       59.99     800x600       60.00    60.32    56.25     840x525       60.01    59.88     800x512       60.17     700x525       59.98     640x512       60.02     720x450       59.89     640x480       60.00    59.94     680x384       59.80    59.96     576x432       60.06     512x384       60.00     400x300       60.32    56.34     320x240       60.05  VGA-1-1 disconnectedHDMI-1-1 disconnectedDP-1-1 disconnectedlspci | grep VGA output00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)01:00.0 VGA compatible controller: NVIDIA Corporation GF108M [GeForce GT 540M] (rev a1)xorg.confSection ServerLayout    Identifier layout    Screen 0 nvidia    Inactive intelEndSectionSection Device    Option         Coolbits 28    Identifier intel    Driver modesetting    BusID PCI:0@0:2:0    Option AccelMethod NoneEndSectionSection Screen    Identifier intel    Device intelEndSectionSection Device    Option         Coolbits 28    Identifier nvidia    Driver nvidia    BusID PCI:1@0:0:0    Option ConstrainCursor offEndSectionSection Screen    Identifier nvidia    Device nvidia    Option AllowEmptyInitialConfiguration on    Option CoolBits 31    Option RegistryDwords PowerMizerEnable=0x1; PerfLevelSrc=0x2222; PowerMizerDefault=0x2; PowerMizerDefaultAC=0x2    Option OnDemandVBlankInterrupts trueEndSectionThe line Option RegistryDwords PowerMizerEnable=0x1; PerfLevelSrc=0x2222; PowerMizerDefault=0x2; PowerMizerDefaultAC=0x2 is needed because my GPU needs to be underclocked to work properly. Works fine on my laptop screen, I believe it's not the problem. If I remove the line, the screen freezes 10 seconds after login.I have tried toReinstall nvidia driversReconnect HDMI (like a thousand times)All the answers to this 
Second monitor doesn't work with nvidia drivers
ubuntu;xorg;drivers;nvidia;graphics