How can i remove this script blocking Facebook & YouTube from my browser ?

[saumit]

Hi guys , i need some help what happened is i was little addicted to Fb (Facebook) so i didn't got time to study for my exams. I have Windows XP. I have putsome screenshots too which starts from http://www.wikihow.com/Study and the 13th tip of it is :-
13. If you are easily distracted by social networking sites such as YouTube, Facebook, etc, then download application LetMeWork at :
http://img.labnol.org/files/18257/letmework.zip. Tried and tested, this will temporarily block these sites and help you study better. Double-click it to instantly block some of the distracting sites on your computer. When you are done with your work, double-click the same file again to unblock access to all the sites as before.
so this http://prntscr.com/1yaozq first before reading next) the one which is in box and one more script which is below the box is done maybe after the download . Please tell me what to do and the blocking is on my all browsers.

[Zarn]

Make a separate account for your cousin. Whatever software you've got installed, won't be installed for your cousin.