Installation failed for component Microsoft .NET Framework 2.0a. MSI returned error code 1603

win2003  安装了 sql2008 出现问题，重新卸载再安装.net，报错

 

解决步骤：

1、添加注册表

After 22 hours of troubleshooting, I finally got to the root of the problem in my case! This may not work for everyone though

In regedit, browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\Security\

Check for the existence of a key named 'ServiceModel 3.0.0.0' (without the quotes)

If it doesn't exist, create it.

Add Administators and give them Full Control in permissions.

Also add Full Control permission for System

I also added Everyone and gave Full Control as well, but I don't think this is necessary.

If your own user account is showing there, delete it.

Problem solved on the next install - now I can get some sleep!!

2、使用 Microsoft .NET Framework Cleanup Tool v2018.05免费中文版.exe 卸载所有

3、C:\WINDOWS\assembly 重新命名

4、重启

5、启动之后，关闭SQL2005所有服务  360等软件

6、直接安装.net3.5sp1   dotnetfx35.exe 

7、安装完成之后  .net 2  net3.5 都自动安装上