Can't install .NET Framework 3.5 on Vista

Question

I tried several times to install .NET Framework 3.5 and Visual Studio 2008 on my machine.
I am getting an error during installation Set Up.exe has stopped working and the installation fails.
I am using windows vista. Is there any way to solve it and install Visual Studio 2008.
I was running Visual Studio 2005 before and I unintalled it completely.
Thanks