1. Updating Software Sources
Go to System -> Administration -> Software Sources
click the Updates tab.

2. Updating your system
There are two ways to update. One is by going to System -> Administration -> Update Manager and the other one is by using the Terminal (Applications -> Accessories -> Terminal) and type this code: sudo apt-get update
3. Adding third party repository: MEDIBUNTU
Pls check this link for instructions: https://help.ubuntu.com/community/Medibuntu
4. Enable ubuntu-restricted-extras
By default, ubuntu won't let you use proprietary codecs which enables us to watch movie and listen to mp3s. Ubuntu-restricted-extras allows as to do this. To install; open terminal and type sudo apt-get install ubuntu-restricted-extras.
5. Install VLC
VLC is the best movie player! To install go to terminal and type sudo apt-get install vlc.