Shutdown failed (WinMySQLAdmin)

[ikm]

I am freshly install MySQL on my computer with Windows 98 as operating system.
I used MySQL ver. 3.23.58-max-debug. I am new user of MySQL and have problem when 
shuttingdown "WinMySQLAdmin".
The error as this:
        Error on shutdown:
        Access denied for user: '@localhost' (Using password: NO)

For information, My Computer was setting as this:
        Local Host Name : USER
        Local User Name : ADI
        OS Platform        : Windows 98
MySQL was setting as this:
        [MySQLD] 
        basedir=C:/Program Files/mySQL/
        datadir=C:/Program Files/mySQL/data/
        skip-innodb

        [WinMySQLAdmin]
        Server=C:/PROGRAM FILES/MYSQL/bin/mysqld.exe

And I use MySQL for single user (only my computer)
Beside this problem I need information how to create other user in MySQL.

Thank's for information
Regard's

Muliadi