I can't install SQL Server Management Studio for SQL2008

I can’t install SQL Server Management Studio for SQL Server 2008. I already install the IIS, run the WPI, install all the obtions of the Web Platform, and it did install everything but the Server Management Studio. What can I do?

What happens when you try to install the management studio?

It says that there is some compatibility issue. When I ask the installer to look for solutions in the web, it sends me to a page describing how to install the Server Management service Pack1. Then it says that for me to be able to install this pack, I have to install first the .NET Framework
I tried to install one by one all the different versions of this .NET, but once again, it only says that there are some compatibility issues and send me again to the same page with the informations about the Service Pack 1.