How to set the root password?

Hello!

I try to install mysql but I can not set the new root password right.

When I install mysql I can log in without any password like:

C:\mysql\bin>mysql -u root -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4 to server version: 3.23.49-max-nt

Type 'help;' or '\h' for help. Type '\c' to clear the buffer.

mysql>

But if I try to change it like:

UPDATE user SET Password=PASSWORD('mupmup') WHERE user='root';

Or like in the manual:

C:\> C:\mysql\bin\mysql mysql
mysql> DELETE FROM user WHERE Host='localhost' AND User='';
mysql> QUIT
C:\> C:\mysql\bin\mysqladmin reload
C:\> C:\mysql\bin\mysqladmin -u root password mupmup

I can not log in again I just get:

C:\mysql\bin>mysql -u root -p
Enter password: ******
ERROR 1045: Access denied for user: 'root@localhost' (Using password: YES)

So if any one got any idea please let me know!

Best regards
Fredrik