Safety on social networking sites is important, and this means taking care regarding who can see your Facebook profile. Facebook makes it easy to keep most aspects of your profile -- including your wall and photo albums -- hidden from everyone but friends. If one user in particular is not welcome to contact you, you can block her altogether. When you block someone, you become completely invisible to her on Facebook -- she will never see your comments on another user's page and you won't turn up in her searches.
Click on the "Account" link in the top right corner of any Facebook screen.
Select "Privacy Settings" from the drop-down menu.
Scroll down to the "Block Lists" section of the page, located under the "Sharing on Facebook" chart.
Click on the blue "Edit your Lists" link in the Block Lists section.
Enter the name of the user you want to block in the "Name" field and click "Block this User." Facebook searches for people with that name and shows you a list of matches. Select a user by clicking the "Block" icon to the right of her name.
Click on the "Account" link in the top right corner of any Facebook screen.
Select "Privacy Settings" from the drop-down menu.
Scroll down to the "Block Lists" section of the page, located under the "Sharing on Facebook" chart.
Click on the blue "Edit your Lists" link in the Block Lists section.
Enter the name of the user you want to block in the "Name" field and click "Block this User." Facebook searches for people with that name and shows you a list of matches. Select a user by clicking the "Block" icon to the right of her name.