Unable to install Visual Studio 2008 on Windows 2008 R2

I am trying to install Visual Studio 2008 on my Windows 2008 R2 machine.
This is the first time I am using the Windows 2008 R2 machine and I was wondering why I am getting the following error message.

Microsoft .NET Framework 3.5 Setup
You must use the Role Management Tool to install or configure
Microsoft. NET Framework 3.5.
OK
I see that the machine already is installed with .NET 3.5.1 framework, but somehow it is not being recognized.
Does anyone have any idea about this error message?
When I read and analyze the error message while installing the utility, I am deeply troubled what might be the cause of this error, I turn OFF and ON my computer to have a fresh start, when I tried again doing the same process, still the same error appeared, I also scan my computer for some virus, but no virus was found, please share your ideas on this scenario, thanks a lot.
