How to block Facebook on a computer?

[RaNdOm]

okay everytime someone goes on facebook on one of my computers you can tell because it slows down and gets a bad virus (sometimes even my security can't handle it!)
how do you block facebook
no it's not that but thank you
telling them that is like talking to a brick wall...it won't work
:/
ive tried that

[Farmress]

if you got kids under 13, they should not be allowed on Facebook. You can report them insite or set up parenting blocks from your computer. Contact the ISP for more info.

[?]

Just tell everyone not to get on facebook thats the best thing cuz u can't really block it unless u talk to the internet sources awry can't help but just thought I answer with the best I can come up with