Thank to http://www.justanswer.com/computer-programming/1tglx-i-ve-forgotten-mysql-password-wamp-can-t-logon.html
In case you forgot the root password XXXXX your MySQL database server running under Microsoft Windows, you can still access your database and even reset your password XXXXX the command prompt. However, first you should check your my.cnf file where your password XXXXX XXXXX
If you are using a new version of MySQL Server, such as 5.0, the methods here might not work for you, or slightly different actions may need to be applied.
1. Stop your MySQL server completely. This can be done by accessing the Services window inside Windows XP and Windows Server 2003, where you can stop the MySQL service.
2. Open your MS-DOS command prompt using “cmd” inside the Run window. Inside it navigate to your MySQL bin folder, such as C:\MySQL\bin using thecd command.
3. Execute the following command in the command prompt: mysqld.exe -u root –skip-grant-tables
4. Leave the current MS-DOS command prompt as it is, and open a new MS-DOS command prompt window.
5. Navigate to your MySQL bin folder, such as C:\MySQL\bin using the cd command.
6. Enter “mysql” and press enter.
7. You should now have the MySQL command prompt working. Type “use mysql;” so that we switch to the “mysql” database.
8. Execute the following command to update the password:
UPDATE user SET Password = PASSWORD(‘NEW_PASSWORD’) WHERE User = ‘root’;
However, you can now run any SQL command that you wish.
After you are finished close the first command prompt and type “exit;” in the second command prompt windows to disconnect successfully. You can now start the MySQL service.