Commonly used commands to fix Virtualbox (Ubuntu and GPU related issues)

Fixed Virtualbox by running:
sudo apt-get remove --purge nvidia-*
sudo apt-get install ubuntu-desktop


sudo rm /etc/X11/xorg.conf

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sudo apt-get install gnome-session ubuntu-desktop

sudo apt-get install --reinstall linux-image-$(uname -r)

sudo apt-get --reinstall install libgl1-mesa-glx

# Also check ~/.xsession-errors
# /var/log/Xorg.0.log
# /var/log/lightdm/lightdm.log
# /var/log/lightdm/x-0-greeter.log

# If no menu bar
setsid unity

sudo apt install --reinstall lightdm
sudo apt install --reinstall nvidia-XXX
sudo apt install --reinstall xserver-xorg
sudo apt install --reinstall xserver-xorg-core

sudo apt install --reinstall gnome-session

sudo dpkg-reconfigure xserver-xorg

# Unable to mount the Guest Additsudo mkdir --p /media/cdrom
sudo mount -t auto /dev/cdrom /media/cdrom/
cd /media/cdrom/
sudo sh VBoxLinuxAdditions.run