This is not actually hacking facebook account but preventing the victim to login into his facebook account.
Principle behind working:
Facebook has security feature in which after 25 or so logins the account is temporarily disabled,to enablethe account the account owner must reset his/her account
Thus, even when victim tries to login his Facebook account using correct password, he is not able to login to his Facebook account, thus you can hack Facebook account thanks to Facebook Freezer.
This Facebook Freezer works cool on windows xp and windows vista (even supports earlier version of windows).