1.,到控制面板里面先把mysql删除.
2.到c盘C:\Program Files目录下把mysql目录删除.
3.如果在其他盘还有设置目录也要删除.空目录也要删除.删除C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.1/data目录下ib_logfile0、ib_logfile1两个文件删除，顺便说句，此目录下有个err文件，是以主机名命名的，里面记载着错误信息，类似下面这段：
InnoDB: The first specified data file E:/Data/ibdata1 did not exist:
InnoDB: a new database to be created!
090501 19:20:08 InnoDB: Setting file E:/Data/ibdata1 size to 10 MB
InnoDB: Database physically writes the file full: wait...
InnoDB: Error: log file ./ib_logfile0 is of different size 0 48234496 bytes
InnoDB: than specified in the .cnf file 0 17825792 bytes!
090501 19:20:09 [ERROR] Plugin 'InnoDB' init function returned error.
090501 19:20:09 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
090501 19:20:09 [ERROR] Unknown/unsupported table type: INNODB
090501 19:20:09 [ERROR] Aborting
090501 19:20:09 [Warning] Forcing shutdown of 1 plugins
090501 19:20:09 [Note] E:/Program Files/MySQL/MySQL Server/bin/mysqld: Shutdown complete
4.到regedit把注册表
HKEY_LOCAL_MACHINE/SYSTEM/ControlSet001/Services/Eventlog/Applications/MySQL
HKEY_LOCAL_MACHINE/SYSTEM/ControlSet002/Services/Eventlog/Applications/MySQL
HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Eventlog/Applications/MySQL
有的话,全部删除！
（技巧：用F3循环查找“mysql”）
5.如果任务管理器里有关mysql内容也删除