blocking facebook,hotmail from being accessed via interenet explorer

I receive your newsletters and have at some point read through one and found a way to prevent my son from logining on to facebook and/or hotmail,,via internet explorer. This was perhaps 1 year ago, I have had a stroke since that time and now I am trying to reverse what I did and I cannot find the article or anything that points me in that direction.
If somone could please provide me with some help, it would be greatly appreciated.