From Israel21c:

Jan. 21 – The chief rabbi of the city of Safed, Shlomo Eliyahu, has composed a special prayer for those who have accidentally entered pornographic sites or have had those sites pop up unannounced on their screens. Yediot Aharonot reported that concerned religious surfers contacted Rabbi Eliyahu,telling him that they had accidentally entered pornographic sites while surfing. On hearing this, Eliyahu composed a special prayer for protection from entering pornographic sites by accident: “Please, God, help me to cleanse my computer of all sorts of viruses and evil images that spoil and interfere with my lawful work, and allow me to cleanse myself so that I may be pure of mind and may pray with a perfect heart, and that I may raise a family in true, stable love.” Eliyahu said that the prayer should be said every time one goes onto the Internet.

Me, I’m sticking with AVG.