Go to C:\Windows\System32\drivers\etc\ and open hosts with notepad
Delete all like this:

173.252.110.27 facebook.com
173.252.112.23 www.facebook.com
173.252.112.23 login.facebook.com
69.171.242.27 upload.facebook.com
66.220.152.19 graph.facebook.com
173.252.101.48 pixel.facebook.com
173.252.100.27 apps.facebook.com

Save file. Enjoy!

P/S: Sorry if my English bad. I'm from Vietnam

Go to C:\Windows\System32\drivers\etc\ and open hosts in Notepad.

Delete all entries like this:

173.252.110.27 facebook.com
173.252.112.23 www.facebook.com
173.252.112.23 login.facebook.com
69.171.242.27 upload.facebook.com
66.220.152.19 graph.facebook.com
173.252.101.48 pixel.facebook.com
173.252.100.27 apps.facebook.com

Save the file.