So I turned on my computer and log into my gnome-shell session to find that the shell is gone, and there is instead a very thick panel with a vertically repeated pattern of the gradient the Unity panel displays. I ran some tests and found out that my graphic acceleration was failing. I have attached some outputs of some commands to help helpers help me:

Some command outputs

Video card: nVidia GeForce 8600M GT (note that it is not an Optimus card). Output of lspci | grep VGA:

01:00.0 VGA compatible controller: NVIDIA Corporation G84 [GeForce 8600M GT] (rev a1)

Output of glxinfo:

Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Error: couldn't find RGB GLX visual or fbconfig

Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".
Xlib:  extension "GLX" missing on display ":0.0".

Contents of /var/log/Xorg.0.log:

NVIDIA: Failed to load the NVIDIA kernel module. Please check your
NVIDIA:     system's kernel log for additional error messages.
UnloadModule: "nvidia"
Unloading nvidia
Failed to load module "nvidia" (module-specific error, 0)

If I use the Aditional Drivers system application, I see none of the drivers active, and when I try to activate any, I get an error telling me to check the jockey.log file. The contents of /var/log/jockey.log are:

2012-09-20 23:11:32,690 DEBUG: NVidia(nvidia_173).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:32,690 DEBUG: nvidia_173 is not the alternative in use
2012-09-20 23:11:34,606 DEBUG: BroadcomWLHandler enabled(): kmod disabled, bcm43xx: blacklisted, b43: enabled, b43legacy: enabled
2012-09-20 23:11:34,657 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:34,657 DEBUG: nvidia_173_updates is not the alternative in use
2012-09-20 23:11:36,647 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:36,648 DEBUG: KMH enabled: False
2012-09-20 23:11:38,642 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:38,642 DEBUG: nvidia_current_updates is not the alternative in use
2012-09-20 23:11:40,546 DEBUG: NVidia(nvidia_173).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:40,546 DEBUG: nvidia_173 is not the alternative in use
2012-09-20 23:11:40,620 DEBUG: NVidia(nvidia_173).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:40,620 DEBUG: nvidia_173 is not the alternative in use
2012-09-20 23:11:40,629 DEBUG: BroadcomWLHandler enabled(): kmod disabled, bcm43xx: blacklisted, b43: enabled, b43legacy: enabled
2012-09-20 23:11:40,698 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:40,698 DEBUG: nvidia_173_updates is not the alternative in use
2012-09-20 23:11:40,759 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:40,760 DEBUG: KMH enabled: False
2012-09-20 23:11:40,826 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:40,826 DEBUG: nvidia_current_updates is not the alternative in use
2012-09-20 23:11:45,415 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:45,415 DEBUG: KMH enabled: False
2012-09-20 23:11:47,367 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:11:47,367 DEBUG: KMH enabled: False
2012-09-20 23:11:55,961 WARNING: modinfo for module nvidia_current failed: ERROR: modinfo: could not find module nvidia_current

2012-09-20 23:11:55,962 ERROR: XorgDriverHandler.enable(): package or module not installed, aborting
2012-09-20 23:12:27,780 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:27,781 DEBUG: KMH enabled: False
2012-09-20 23:12:27,840 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:27,840 DEBUG: KMH enabled: False
2012-09-20 23:12:43,196 DEBUG: NVidia(nvidia_173).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,197 DEBUG: nvidia_173 is not the alternative in use
2012-09-20 23:12:43,208 DEBUG: BroadcomWLHandler enabled(): kmod disabled, bcm43xx: blacklisted, b43: enabled, b43legacy: enabled
2012-09-20 23:12:43,269 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,269 DEBUG: nvidia_173_updates is not the alternative in use
2012-09-20 23:12:43,333 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,333 DEBUG: KMH enabled: False
2012-09-20 23:12:43,393 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,394 DEBUG: KMH enabled: False
2012-09-20 23:12:43,465 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,465 DEBUG: nvidia_current_updates is not the alternative in use
2012-09-20 23:12:43,531 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,531 DEBUG: KMH enabled: False
2012-09-20 23:12:43,587 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,587 DEBUG: KMH enabled: False
2012-09-20 23:12:43,663 DEBUG: NVidia(nvidia_173).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,663 DEBUG: nvidia_173 is not the alternative in use
2012-09-20 23:12:43,672 DEBUG: BroadcomWLHandler enabled(): kmod disabled, bcm43xx: blacklisted, b43: enabled, b43legacy: enabled
2012-09-20 23:12:43,738 DEBUG: NVidia(nvidia_173_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,739 DEBUG: nvidia_173_updates is not the alternative in use
2012-09-20 23:12:43,803 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,803 DEBUG: KMH enabled: False
2012-09-20 23:12:43,863 DEBUG: NVidia(nvidia_current).enabled(): target_alt /usr/lib/nvidia-current/ld.so.conf current_alt /usr/lib/nvidia-current/ld.so.conf other target alt /usr/lib/nvidia-current/alt_ld.so.conf other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,863 DEBUG: KMH enabled: False
2012-09-20 23:12:43,930 DEBUG: NVidia(nvidia_current_updates).enabled(): target_alt None current_alt /usr/lib/nvidia-current/ld.so.conf other target alt None other current alt /usr/lib/nvidia-current/alt_ld.so.conf
2012-09-20 23:12:43,930 DEBUG: nvidia_current_updates is not the alternative in use
2012-09-20 23:24:16,305 DEBUG: Shutting down

Things I have tried

• Checked the video card on a Windows session.
• Reran nvidia-xconfig.
• Purged all nvidia software from my computer, and reinstall it. Run nvidia-xconfig.
• Tried a different kernel.