XNA Game Studio 2.0安装问题，崩溃了

安装后给了个提示:
      

Microsoft XNA Game Studio 2.0 Setup ended prematurely due to an error.Your system has not been modified.To install this

program at a later time,please run the installation again.

   不知道杂搞了，VS2005+Sp1都重装过，好几天了。