I have recently upgraded my graphics card from a GTX 760 to a GTX 1070. When I started up Linux, I got an error in lightdm. I assumed this was standard and I just needed to install the new drivers, so I pressed CTRL-ALT-F2 and ran # apt-get upgrade nvidia*. This command got stuck several times over, and I needed to prod it along with ^C. Needless to say, this didn't solve the problem.I tried a few other solutions, including commenting out the Nvidia block in the Xorg.conf file:# -xconfig: X configuration file generated by nvidia-xconfig# nvidia-xconfig:  version 340.46  (buildd@brahms)  Tue Oct  7 08:00:32 UTC 2014Section ServerLayout    Identifier     Layout0    Screen      0  Screen0    InputDevice    Keyboard0 CoreKeyboard    InputDevice    Mouse0 CorePointerEndSectionSection FilesEndSectionSection InputDevice    # generated from default    Identifier     Mouse0    Driver         mouse    Option         Protocol auto    Option         Device /dev/psaux    Option         Emulate3Buttons no    Option         ZAxisMapping 4 5EndSectionSection InputDevice    # generated from default    Identifier     Keyboard0    Driver         kbdEndSectionSection Monitor    Identifier     Monitor0    VendorName     Unknown    ModelName      Unknown    HorizSync       28.0 - 33.0    VertRefresh     43.0 - 72.0    Option         DPMSEndSectionSection Device #I commented out from here    Identifier     Device0    Driver         nvidia    VendorName     NVIDIA CorporationEndSection #to hereSection Screen    Identifier     Screen0    Device         Device0    Monitor        Monitor0    DefaultDepth    24    SubSection     Display        Depth       24    EndSubSectionI was hoping that this would make Xorg stop trying to use the Nvidia drivers and instead use the ones already in the kernel. Instead, when I ran service lightdm start, my monitor went black and gave the message Not supported. I cannot seem to get out of this: I tried stopping the lightdm service, restarting the computer, running Xorg :1 -configure, reinstalling the nvidia drivers, and reinstalling my DE.I currently am connected to my computer via SSH, so I cannot do anything that would require changing the network settings.Here are some other logs that may or may not be useful:# lspci 00:00.0 Host bridge: Intel Corporation 4th Gen Core Processor DRAM Controller (rev 06)00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor PCI Express x16 Controller (rev 06)00:14.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB xHCI (rev 05)00:16.0 Communication controller: Intel Corporation 8 Series/C220 Series Chipset Family MEI Controller #1 (rev 04)00:1a.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #2 (rev 05)00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 05)00:1c.0 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #1 (rev d5)00:1c.2 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #3 (rev d5)00:1c.5 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #6 (rev d5)00:1d.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #1 (rev 05)00:1f.0 ISA bridge: Intel Corporation Z87 Express LPC Controller (rev 05)00:1f.2 SATA controller: Intel Corporation 8 Series/C220 Series Chipset Family 6-port SATA Controller 1 [AHCI mode] (rev 05)00:1f.3 SMBus: Intel Corporation 8 Series/C220 Series Chipset Family SMBus Controller (rev 05)01:00.0 VGA compatible controller: NVIDIA Corporation Device 1b81 (rev a1)01:00.1 Audio device: NVIDIA Corporation Device 10f0 (rev a1)03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)04:00.0 Network controller: Qualcomm Atheros AR9485 Wireless Network Adapter (rev 01)# service lightdm status lightdm.service - Light Display Manager   Loaded: loaded (/lib/systemd/system/lightdm.service; enabled)   Active: failed (Result: start-limit) since Thu 2017-01-12 20:48:12 EST; 24min ago     Docs: man:lightdm(1) Main PID: 11896 (code=exited, status=1/FAILURE)Jan 12 20:48:12 homebox systemd[1]: lightdm.service: main process exited, code=exited, status=1/FAILUREJan 12 20:48:12 homebox systemd[1]: Unit lightdm.service entered failed state.Jan 12 20:48:12 homebox systemd[1]: lightdm.service holdoff time over, scheduling restart.Jan 12 20:48:12 homebox systemd[1]: Stopping Light Display Manager...Jan 12 20:48:12 homebox systemd[1]: Starting Light Display Manager...Jan 12 20:48:12 homebox systemd[1]: lightdm.service start request repeated too quickly, refusing to start.Jan 12 20:48:12 homebox systemd[1]: Failed to start Light Display Manager.Jan 12 20:48:12 homebox systemd[1]: Unit lightdm.service entered failed state.# XorgX.Org X Server 1.16.4Release Date: 2014-12-20X Protocol Version 11, Revision 0Build Operating System: Linux 3.16.0-4-amd64 x86_64 DebianCurrent Operating System: Linux homebox 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64Kernel command line: BOOT_IMAGE=/vmlinuz-3.16.0-4-amd64 root=UUID=572d5efa-5f06-4960-a090-810a2baf440b ro initrd=/install/initrd.gz quietBuild Date: 11 February 2015  12:32:02AMxorg-server 2:1.16.4-1 (http://www.debian.org/support) Current version of pixman: 0.32.6    Before reporting problems, check http://wiki.x.org    to make sure that you have the latest version.Markers: (--) probed, (**) from config file, (==) default setting,    (++) from command line, (!!) notice, (II) informational,    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.(==) Log file: /var/log/Xorg.0.log, Time: Thu Jan 12 21:13:15 2017(==) Using config file: /etc/X11/xorg.conf(==) Using system config directory /usr/share/X11/xorg.conf.d(EE) Fatal server error:(EE) no screens found(EE) (EE) Please consult the The X.Org Foundation support      at http://wiki.x.org for help. (EE) Please also check the log file at /var/log/Xorg.0.log for additional information.(EE) (EE) Server terminated with error (1). Closing log file.# cat /var/log/Xorg.0.log[  2268.438] X.Org X Server 1.16.4Release Date: 2014-12-20[  2268.438] X Protocol Version 11, Revision 0[  2268.438] Build Operating System: Linux 3.16.0-4-amd64 x86_64 Debian[  2268.438] Current Operating System: Linux homebox 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u2 (2016-10-19) x86_64[  2268.438] Kernel command line: BOOT_IMAGE=/vmlinuz-3.16.0-4-amd64 root=UUID=572d5efa-5f06-4960-a090-810a2baf440b ro initrd=/install/initrd.gz quiet[  2268.438] Build Date: 11 February 2015  12:32:02AM[  2268.438] xorg-server 2:1.16.4-1 (http://www.debian.org/support) [  2268.438] Current version of pixman: 0.32.6[  2268.438]    Before reporting problems, check http://wiki.x.org    to make sure that you have the latest version.[  2268.438] Markers: (--) probed, (**) from config file, (==) default setting,    (++) from command line, (!!) notice, (II) informational,    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.[  2268.438] (==) Log file: /var/log/Xorg.0.log, Time: Thu Jan 12 21:13:15 2017[  2268.439] (==) Using config file: /etc/X11/xorg.conf[  2268.439] (==) Using system config directory /usr/share/X11/xorg.conf.d[  2268.439] (==) ServerLayout Layout0[  2268.439] (**) |-->Screen Screen0 (0)[  2268.439] (**) |   |-->Monitor Monitor0[  2268.439] (**) |   |-->Device Device0[  2268.439] (**) |-->Input Device Keyboard0[  2268.439] (**) |-->Input Device Mouse0[  2268.440] (==) Automatically adding devices[  2268.440] (==) Automatically enabling devices[  2268.440] (==) Automatically adding GPU devices[  2268.440] (WW) The directory /usr/share/fonts/X11/cyrillic does not exist.[  2268.440]    Entry deleted from font path.[  2268.440] (==) FontPath set to:    /usr/share/fonts/X11/misc,    /usr/share/fonts/X11/100dpi/:unscaled,    /usr/share/fonts/X11/75dpi/:unscaled,    /usr/share/fonts/X11/Type1,    /usr/share/fonts/X11/100dpi,    /usr/share/fonts/X11/75dpi,    built-ins[  2268.440] (==) ModulePath set to /usr/lib/xorg/modules[  2268.440] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled.[  2268.440] (WW) Disabling Keyboard0[  2268.440] (WW) Disabling Mouse0[  2268.440] (II) Loader magic: 0x7f00cc8b7d80[  2268.440] (II) Module ABI versions:[  2268.440]    X.Org ANSI C Emulation: 0.4[  2268.440]    X.Org Video Driver: 18.0[  2268.440]    X.Org XInput driver : 21.0[  2268.440]    X.Org Server Extension : 8.0[  2268.441] (--) PCI:*(0:1:0:0) 10de:1b81:3842:6171 rev 161, Mem @ 0xf6000000/16777216, 0xe0000000/268435456, 0xf0000000/33554432, I/O @ 0x0000e000/128, BIOS @ 0x????????/524288[  2268.441] (II) LoadModule: glx[  2268.441] (II) Loading /usr/lib/xorg/modules/linux/libglx.so[  2268.454] (II) Module glx: vendor=NVIDIA Corporation[  2268.454]    compiled for 4.0.2, module version = 1.0.0[  2268.454]    Module class: X.Org Server Extension[  2268.454] (II) NVIDIA GLX Module  340.96  Sun Nov  8 22:06:18 PST 2015[  2268.454] (II) LoadModule: nvidia[  2268.454] (II) Loading /usr/lib/xorg/modules/drivers/nvidia_drv.so[  2268.455] (II) Module nvidia: vendor=NVIDIA Corporation[  2268.455]    compiled for 4.0.2, module version = 1.0.0[  2268.455]    Module class: X.Org Video Driver[  2268.455] (II) NVIDIA dlloader X Driver  340.96  Sun Nov  8 21:46:28 PST 2015[  2268.455] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs[  2268.455] (--) using VT number 3[  2268.465] (II) Loading sub module fb[  2268.465] (II) LoadModule: fb[  2268.465] (II) Loading /usr/lib/xorg/modules/libfb.so[  2268.465] (II) Module fb: vendor=X.Org Foundation[  2268.465]    compiled for 1.16.4, module version = 1.0.0[  2268.465]    ABI class: X.Org ANSI C Emulation, version 0.4[  2268.465] (WW) Unresolved symbol: fbGetGCPrivateKey[  2268.465] (II) Loading sub module wfb[  2268.465] (II) LoadModule: wfb[  2268.465] (II) Loading /usr/lib/xorg/modules/libwfb.so[  2268.465] (II) Module wfb: vendor=X.Org Foundation[  2268.465]    compiled for 1.16.4, module version = 1.0.0[  2268.465]    ABI class: X.Org ANSI C Emulation, version 0.4[  2268.465] (II) Loading sub module ramdac[  2268.465] (II) LoadModule: ramdac[  2268.465] (II) Module ramdac already built-in[  2268.468] (EE) NVIDIA: Failed to initialize the NVIDIA kernel module. Please see the[  2268.468] (EE) NVIDIA:     system's kernel log for additional error messages and[  2268.468] (EE) NVIDIA:     consult the NVIDIA README for details.[  2268.468] (EE) No devices detected.[  2268.468] (EE) Fatal server error:[  2268.468] (EE) no screens found(EE) [  2268.468] (EE) Please consult the The X.Org Foundation support      at http://wiki.x.org for help. [  2268.468] (EE) Please also check the log file at /var/log/Xorg.0.log for additional information.[  2268.468] (EE) 
Monitor no longer working after upgrading graphics card
xorg;nvidia;graphics;lightdm