Do you know any computer programs that is able to block certain web sites?

I'm trying to block a web site that I'm addicted to and is harmful to me. Does anyone know any computer program that is able to block web sites that I am unable to do the result or takes me hours and hours to unlock so that would be a huge deterrent.

• We will miss you so much.

• R1, it's not the DL I want to block.

• You should ask someone who has kids. Isn't Net Nanny a thing?

• But you'd always hold the key to the Pandora's Box!!!!

  Temptressa