Why can't I change the password of MySQL database under Wamp server environment?

Each time this console, do not enter the password can be used directly, with the root login is not. Changing the root password will not change. Confused?

After a constant attempt to finally find a solution:

1, add skip-grant-tables at the end of MySQL config file My.ini, save, restart MySQL

2, direct no password login MySQL

3, typing command: use MySQL

4,update user SET Password=password ("New password") WHERE user= ' username ';

5, see the prompt changes successfully, remove My.ini end of skip-grant-tables, restart MySQL database

6, enter the password just changed login success, the original empty password has been unable to use.

Why can't I change the password of MySQL database under Wamp server environment?