How Do I Get Rid of Differentia.ru/diff.php Constant Pop-up?

Hello. I started getting popups from http://differentia.ru/diff.php and they haven't stopped. I was hoping to get some help as to how I can get this malware cleaned from my system.

What is Differentia.ru/diff.php?

Differentia.ru/diff.php is an annoying redirect infection that always tries to invade users’ computers as a pop-up window. It affects all sorts of web browsers so anyone who gets infected will not use his browser normally. Why this pop-up keeps coming up? That is because your computer has infected by certain malware, namely browser hijacker.