I installed the .NET Framework during my Studio installation but when I launch the installer again it asks to install .NET again.
From Fretlight Knowledgebase
(Redirected from I installed the .NET Framework during my Studio installation on my XP but when I launch the installer again it asks to install .NET again.)
Please download the 3.5 SP1 version of .NET Framework from Microsoft:
http://www.microsoft.com/download/en/confirmation.aspx?id=22
After you install 3.5. restart the Studio's installer and continue with the installation as normal.