Mysql Password OLD and NEW

due to upgrade (for MySQL>4.1) the password changes & that needs to be reset by something like:
(at MySQL prompt)
-------------------------------------------------------------------------------------------------------------------
UPDATE mysql.user SET password=OLD_PASSWORD('your_old_password') WHERE user='your_user' AND host='your_hostname';
-------------------------------------------------------------------------------------------------------------------

Then, you need to flush the privileges (at MySQL prompt):
----------------------------------------------------------
flush privileges;
----------------------------------------------------------
This ussualy happend when you upgrade the client or new installation of apache but using the old MYSQL package from mysql.com