in the top, click settings, then on the bottom select deactivate account
1. Make sure your Facebook account contains a contact e-mail address (such as Yahoo or Gmail).
2. Delete any college, high school, or work e-mail addresses listed in your Facebook account. Your contact e-mail should be the only address listed.
3. Deactivate your Facebook account. (Under Settings)
4. Register using an e-mail address other than your contact e-mail (a college, high school, or work e-mail is fine).
5. Once you are signed into your new Facebook account, add your contact e-mail address to the account. Open the link in the confirmation e-mail that has been sent. This step will wipe out your previous Facebook account, rendering it inaccessible.

Hope it helps you.
Look to your upper left just below your address bar it says

Your name Setting Logout

Now put your mouse on setting and 3 options will appear
Account setting
Privacy setting
Application setting

Click on account setting

Then you will get a page that has 6 tabs on it , you'll be directed to the right one
Then scroll down and it says deactivate account now go to your left and click the deactivate account words in tiny blue'
and then you give them a reason for why you're doing that and you submit. Hope it worked. I did it once but my account is still there. Stupid facebook.
you go to settings and click on account settings

scroll down to the bottom of the first page and it has deactivate account and u click on deactivate and follow the instructions