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 trusty contrib

Ubuntu 13.10
deb saucy contrib


Import the VirtualBox repository Public key to your system.

#   wget

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

#  apt-get update

#  apt-get  install virtualbox-4.3

Option 2:

Another Option is just download the backages from oracle and Install it.
# wget

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


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) ...