http://niu174420064.iteye.com/blog/875908
错误说明：
在安装mysql的时候，就会遇到以下错误。遇到错误不可怕，怕的就是被错误所击倒！
The security settings could not be applied to the database because the connection has failed with the following error.
Error Nr. 1045
Access denied for user 'root'@'localhost' (using password: YES)
If a personal firewall is running on your machine, please make sure you have opened the TCP port 3306 for connections. Otherwise no client application can connect to the server. After you have opened the port please press [Retry] to apply the security settings.
If you are re-installing after you just uninstalled the MySQL server please note that the data directory was not removed automatically. Therefore the old password from your last installation is still needed to connect to the server. In this case please select skip now and re-run the Configuration Wizard from the start menu.
解决方法：
1, 控制面板卸载MySQL
2, 删除目录 C:\Documents and Settings\All Users\Application Data\MySQL
3.只有彻底删除上次install information之后才能安装，为确保起见，去搜索其他的mysql内容，你也有可能在别的地方安装过mysql的。
3, 重新安装MySQL 就好了
如何你C:\Documents and Settings\All Users下没有Application Data文件夹，选择：工具——文件夹选项——查看——选择显示所有文件和文件夹。
关键在于删除原来的目录 C:\Documents and Settings\All Users\Application Data\MySQL
然后重新安装会出现：
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