How to block advertisements on YouTube and other sites.

First you need to download 'Google Chrome' (in my opinion it is the best browser)
http://www.google.com/chrome/intl/en/landing_chrome.html?hl=en

Later go to the 'Google Chrome' app website and download 'AdBlock'
https://chrome.google.com/webstore/detail/gighmmpiobklfepjocnamgkkbiglidom

The top right of you screen should like like this

Difference 


Before

After