How to remove Win 7 security 2012?

Yes my computer has been infected with Win 7 Security i cannot open anything on my computer so downloading anything is not a option as i already have malaware bytes on my computer but it wont let me access it i have no idea what to i cannot get into internet explorer or anything else on my computer please help i need to finish my report and without my main computer i cant do anything because i am currently on my sisters computer that has nothing on it