Ubuntu: How to prevent your computer from lock/suspend/hibernate?

[this process was accomplished using Ubuntu 12.04 LTS]

Install this program, called "Caffeine". It prevents the computer from locking/suspending/hibernating by simulating some key pressing events.

TO INSTALL:
On terminal:
sudo add-apt-repository ppa:caffeine-developers/ppa
sudo apt-get update
sudo apt-get install caffeine

Then just run and configure like you want.

Done!