mysql5.1服务启动不了，实分郁闷
最近在学习MYSQL，网上下一个MY5.1安装包，结果服务启动不了。网上查资料很多，也没搞明白。
特来请教。
以下是错误文件信息。高手们帮忙分析一下，到底是什么原因。重安无数次，有一次成功，重启机器后，服务又启动不了。
郁闷的我想吐。


100428 11:12:15 [Note] Plugin 'FEDERATED' is disabled.
InnoDB: The first specified data file .\ibdata1 did not exist:
InnoDB: a new database to be created!
100428 11:12:16 InnoDB: Setting file .\ibdata1 size to 10 MB
InnoDB: Database physically writes the file full: wait...
100428 11:12:16 InnoDB: Log file .\ib_logfile0 did not exist: new to be created
InnoDB: Setting log file .\ib_logfile0 size to 10 MB
InnoDB: Database physically writes the file full: wait...
100428 11:12:16 InnoDB: Log file .\ib_logfile1 did not exist: new to be created
InnoDB: Setting log file .\ib_logfile1 size to 10 MB
InnoDB: Database physically writes the file full: wait...
InnoDB: Doublewrite buffer not found: creating new
InnoDB: Doublewrite buffer created
InnoDB: Creating foreign key constraint system tables
InnoDB: Foreign key constraint system tables created
100428 11:12:17 InnoDB: Started; log sequence number 0 0
100428 11:12:17 [ERROR] Do you already have another mysqld server running on port: 3306 ?
100428 11:12:17 [ERROR] Aborting

100428 11:12:17 InnoDB: Starting shutdown...
100428 11:12:18 InnoDB: Shutdown completed; log sequence number 0 44233
100428 11:12:18 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:13:33 [Note] Plugin 'FEDERATED' is disabled.
100428 11:13:34 InnoDB: Started; log sequence number 0 44233
100428 11:13:34 [ERROR] Do you already have another mysqld server running on port: 8181 ?
100428 11:13:34 [ERROR] Aborting

100428 11:13:34 InnoDB: Starting shutdown...
100428 11:13:35 InnoDB: Shutdown completed; log sequence number 0 44233
100428 11:13:35 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:14:43 [Note] Plugin 'FEDERATED' is disabled.
100428 11:14:44 InnoDB: Started; log sequence number 0 44233
100428 11:14:44 [ERROR] Do you already have another mysqld server running on port: 8181 ?
100428 11:14:44 [ERROR] Aborting

100428 11:14:44 InnoDB: Starting shutdown...
100428 11:14:45 InnoDB: Shutdown completed; log sequence number 0 44233
100428 11:14:45 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:18:11 [Note] Plugin 'FEDERATED' is disabled.
100428 11:18:11 InnoDB: Started; log sequence number 0 44233
100428 11:18:11 [ERROR] Do you already have another mysqld server running on port: 3306 ?
100428 11:18:11 [ERROR] Aborting

100428 11:18:11 InnoDB: Starting shutdown...
100428 11:18:13 InnoDB: Shutdown completed; log sequence number 0 44233
100428 11:18:13 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:19:32 [Note] Plugin 'FEDERATED' is disabled.
100428 11:19:33 InnoDB: Started; log sequence number 0 44233
100428 11:19:33 [ERROR] Do you already have another mysqld server running on port: 3306 ?
100428 11:19:33 [ERROR] Aborting

100428 11:19:33 InnoDB: Starting shutdown...
100428 11:19:34 InnoDB: Shutdown completed; log sequence number 0 44233
100428 11:19:34 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:20:31 [Note] Plugin 'FEDERATED' is disabled.
InnoDB: Error: log file .\ib_logfile0 is of different size 0 10485760 bytes
InnoDB: than specified in the .cnf file 0 25165824 bytes!
100428 11:20:31 [ERROR] Plugin 'InnoDB' init function returned error.
100428 11:20:31 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
100428 11:20:31 [ERROR] Unknown/unsupported table type: INNODB
100428 11:20:31 [ERROR] Aborting

100428 11:20:31 [Note] E:\mysql\bin\mysqld: Shutdown complete

100428 11:21:44 [Note] Plugin 'FEDERATED' is disabled.
InnoDB: Erro