Remove password hint option in XP service pack-2.

Yesterday one of my friend came to me and told me that he use a login password to open her pc by using XP Service pack-2. Now a days he faced some problem that any person can be login her pc by using password hint option.
This is very difficult to protect her pc. Now he want to remove password hint option.
Is it possible to remove this problem please give me a solution without delete my login account?
