请问怎么改变mysql的系统变量？

Question

C:\WINNT下有mysql的配置文件my.ini
内容是：
#This File was made using the WinMySQLadmin 1.0 Tool
#2000-11-10 13:35:27#Uncomment or Add only the keys that you know how works.
#Read the MySQL Manual for instructions[mysqld]
basedir=C:/Program Files/nusphere/mysql
#bind-address=61.157.33.139
datadir=C:/Program Files/nusphere/mysql/data
#language=C:/Program Files/nusphere/mysql/share/your language directory
#slow query log#=
#tmpdir#=
#port=3306
#set-variable=key_buffer=16M
[WinMySQLadmin]
Server=C:/Program Files/nusphere/mysql/bin/mysqld-nt.exe
user=administrator
password=******