sql无法安装

如果你是卸载后重装出现的问题的话，应该就是没有卸载干净导致的结果，可以执行以下操作：

一、先把MSSQL卸载干净

1.在添加删除程序中把SQL Server卸载 ；
2.把Microsoft SQL
Server文件夹整个删掉；
3.运行regedit命令，进入注册表,删除如下项：
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft
SQL
Server
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSSQLServer
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSSQLSERVER
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SQLSERVERAGENT
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSSQLSERVERADHELPER
HKEY_CURRENT_USER\Software\Microsoft\Microsoft
SQL Server

二、重启后（最好），重装SQLServer2005。
如果是在多核cpu安装sql server2005 ，就参考以下步骤：
1.在命令行输入msconfig,打开BOOT.ini选项卡（英文）或者引导选项卡（中文），选择【高级选项...】,打开后并设置下拉框【处理器数】的值为1，或者【Numeric】选项卡的值为1。点击确定，然后重启电脑，重启电脑设置才能生效。
2.安装SQL Server 2005，这次不会再出现服务无法启动的错误，应该会很顺利。
3.安装Service Package 3，SQL Server SP3补丁。
4.然后再次输入msconfig,打开【常规】选项卡，在常规选项卡上单击正常启动-加载所有设备驱动程序和服务，然后单击确定。
5.重启电脑，一切搞定。

SQL server安装失败，想卸载又卸载不了，这可怎么办呀？

Hi,

Follow these steps before you install SQL Server 2005:
1.Copy the setup files of the release version of SQL Server 2005 to a folder in a local drive.
Note You must copy all the setup files that include the Servers folder and the Tools folder to a local drive.
2.Download the SQL Server 2005 SP2 or SP3 package, and then expand it on the local drive by using the /X parameter. For example, run the following command to expand the package: SQLServer2005SP2-KB921896-x64-ENU.exe /X
For more information about how to obtain SQL Server 2005 SP2 or SP3, click the following article number to view the article in the Microsoft Knowledge Base: 913089
3.Note the full paths to the new .msp files in the expanded update package. For example: D:\temp\SP2\hotfixsql\files\sqlrun_sql.msp
4.At the command prompt, run the Setup.exe file from the release version by using the appropriate path to involve the new .msp file in the setup.
For example, the following command uses the update package to update the SQL Server Database Engine component to the service pack level: D:\temp\Servers\setup.exe HOTFIXPATCH="D:\temp\SQL2005_12Procs\SP2\hotfixsql\files\sqlrun_sql.msp"
Note After you complete this step, the installation of SQL Server 2005 is in a configuration that is unsupported until you have applied the SQL Server service pack.
5.Apply the service pack package by running the setup file(s) in the expanded location. This step applies all service pack components and returns the installation of SQL Server 2005 to a supported state.