I use mysql with php on windows 2003, and I want to assign a passwor to username. I installed a mysql administration software and Mysql Control center, and aslo I have phpmyadmin, I assigned password to root but and write it down to php database configuration file, but my php site couldnt connect to mysql. do you why is it so?.
how can I manage this.

If you have MySQL 4.1 or 5 installed you might need to use old password to set your password in order to log in. Don't know if this is your problem or not, I know other people including myself have run into it.

Read about it here:
http://www.mysql.com/doc/en/Password_hashing.html

I wrote this document a while back
Basic stuff - PHP -MySQL - Apache.

http://www.coe.uncc.edu/~asingh/DOCS/setup_apm.htm

see if it helps