How to hide my facebook profile from others

Here is the situation, I was looking some coments on a frinds photo.

Then, I realized that Someone was also posting there, but I couldent see.
I know who that person is cause (I've seen her profile before, like 2 weeks ago), She's not on my list of frinds. Then I tried to find her again on our in commun friends, but I cant find her ANYWHERE. Is like she doesnt exist animore to ppl who are not on her list.

She probably didnt blocked me, cause I've tried to find her even with others FB profiles (that also dont has her as a Friend).

I wanted to know how did she do it, cause I want to "hide" my prfile from other ppl as well.

ps: I've already tried everything. "Privacy Settings" "Account Settings".
Everything is already on "ONLY FREINDS" and no one can find me on facebook search. But can find me on my friends list and see my comments on others pages (is they have someone in commun with me). What doesnt happen on her case.

I dont think there is any such thing to get hide from every where. Whatever security you apply, but we can see the one from friends list unless the person has blocked you from seeing her profile from anywhere. I guess, she might have deleted her account. Ask your friends having here in their friends list that still she exist on Facebook or not.

For more info, see this:
http://forums.techarena.in/tips-tweaks/1192384.htm
http://forums.techarena.in/active-directory/1199635.htm

i am also facing such kind of things......sometimes he disappers from my facebook profile and also from mutual friends list and then he resumes backs......i m sure he not blocked me. but how can he disappers and come back ....i want to know how?........please reply