Facebook blocked from browser?

[Sevya]

I am trying to help out a friend who's daughter somehow blocked Facebook from her computer. She has tried all of her browsers and none of them will even load the Facebook page, she can log on from her home and a neighbors computer just not her own laptop. I have suggested everything I know to tell her, such as system restoring to an earlier day, clearing cookies and cache. She also checked the firewall under the control panel, but Facebook does not show as something to allow or block. I am completely out of ideas. Any advice is appreciated, thanks.
She is using Firefox by the way. And there are no websites coming up as restricted. And neither one of us knows anything about uninstalling ad-ons.