卸载mssql步骤 1.在添加删除程序里把所有跟sql有关的软件全部卸载 2.关闭服务 net stop MSSQLSERVER net stop MSSQLServerADHelper net stop SQLSERVERAGENT net stop SQLBrowser net stop SQLWriter 3.卸载服务 sc delete MSSQLSERVER sc delete MSSQLServerADHelper sc delete SQLSERVERAGENT sc delete SQLBrowser sc delete SQLWriter 4.删除对应的注册表项 HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Native Client HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server 2005 Redist HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer 5.重命名或者删除sql安装目录 一般在 C:\Program Files\Microsoft SQL Server D:\Program Files\Microsoft SQL Server 6.重启系统,再开始安装