Reseting Passwords

[~*McoreD*~]

i have a big problem. i and my brother are administrators in the windows xp professional. he always needs to be an administrator or else he complains to dad. i have NTFS formatted hdds but i can't stop him resetting my password from user accounts. when he is pissed off with me he does it cos he is an admin. generally what i want is: to stop other administrators resetting/changing another administrator's (my) password. i had a look in computer management and local security policy but couldn't find an option to do that. are there any geek who knows what to do?