1. Press Alt + F2 then type in gksu gedit /etc/hostname
Change old computer name to your new computer name and save.
2. Press Alt + F2 again then type in: gksu gedit /etc/hosts. Then change current computer name to new computer name.
3. Restart your computer.
Go to Terminal and type in hostname. It will show your new computer name.
I named mine "Timon", the silly meerkat from Disney's Lion King. Enjoy!