VirtualBox is helps and powerful Cross-platform Virtualization Software, you can create and run multiple virtual machines in a computer at the same time. Its also possible to running different OS (Operating System) like Linux, Windows,Mac, etc. This software based on X86 system.



Open a apt sources.list file and add the following repository

# vim etc/apt/sources.list

Ubuntu 14.04 
deb http://download.virtualbox.org/virtualbox/debian trusty contrib

Ubuntu 13.10
deb http://download.virtualbox.org/virtualbox/debian saucy contrib


key:

Import the VirtualBox repository Public key to your system.
 

#   wget http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc
 


Saving to: ‘oracle_vbox.asc’



100%[==============================>] 1,734       6.25KB/s   in 0.3s   



2014-11-13 18:25:03 (6.25 KB/s) - ‘oracle_vbox.asc’ saved [1734/1734]



s# sudo apt-key add oracle_vbox.asc

OK

Install:
 
#  apt-get update

#  apt-get  install virtualbox-4.3

Option 2:

Another Option is just download the backages from oracle and Install it.
 
# wget http://download.virtualbox.org/virtualbox/4.3.18/virtualbox-4.3_4.3.18-96516~Ubuntu~raring_i386.deb


Length: 65053654 (62M) [application/x-debian-package]

Saving to: ‘virtualbox-4.3_4.3.18-96516~Ubuntu~raring_i386.deb’



100%[===========================>] 6,50,53,654 228KB/s in 9m 2s  



2014-11-13 18:06:57 (117 KB/s) - ‘virtualbox-4.3_4.3.18-96516~Ubuntu~raring_i386.deb’ saved [65053654/65053654]
# dpkg --install virtualbox-4.3_4.3.18-96516~Ubuntu~raring_i386.deb

Error:

If you may received an error like below, require DKMS packages for virtualbox.


The following packages have unmet dependencies:

 virtualbox : Depends: libgsoap4 but it is not installable

              Recommends: virtualbox-dkms (= 4.3.10-dfsg-1) but it is not going to be installed or

                          virtualbox-source (= 4.3.10-dfsg-1) but it is not going to be installed

              Recommends: virtualbox-qt (= 4.3.10-dfsg-1) but it is not going to be installed

              Recommends: libqt4-opengl (>= 4:4.5.3) but it is not installable

Run the below commands to remove unwanted packages and install again,
 
# sudo apt-get install linux-headers-generic build-essential dkms

# sudo apt-get remove --purge virtualbox-dkms

# sudo apt-get install virtualbox-dkms



How to Uninstall :
 
# dpkg --remove virtualbox-4.3


(Reading database ... 186655 files and directories currently installed.)

Removing virtualbox-4.3 (4.3.18-96516~Ubuntu~raring) ...

Processing triggers for hicolor-icon-theme (0.13-1) ...

Processing triggers for gnome-menus (3.10.1-0ubuntu2) ...

Processing triggers for desktop-file-utils (0.22-1ubuntu1) ...

Processing triggers for mime-support (3.54ubuntu1) ...