how i cam break administrator password(winxp)?

Answer 1

You need access to the server in order to use this. I've used this and not only did it give me the admin password, it gave me everyone else's password in my office.

Just don't do anything you're not supposed to do!

http://insecure.org/sploits/l0phtcrack.lanman.problems.html

Answer 2

Don't waste your time with an ancient vershion of l0phtcrack. It won't work on an XP system anyway. Try this site instead: http://home.eunet.no/pnordahl/ntpasswd/