when u try to set your password u should insert some of characters, u've already choose to set with uniqe characters.
perhaps when u try to lock the windows they are some changes in your system, have you try to check is your "caps lock" is on or off ? sometimes that simple things could make us in trouble. i dunno how to brake it if you try to unlock your computer if you already sure you've inserted the correct password.
but i'll tell one thing, always make more than one administrator in your comp, so if u forget the password u still can use the other account. and i aggree with "1386" and mr "mmelby" to set your password with basic character.
regard
