By the way .NET libraries are located in C:\Windows\assembly on a Win 7 Professional 64bit installation. Don't ask me how I know that.
Blowing up whole content would... ?

(I tried to install it via its redist installer downloaded from Microsoft Download, not Windows Update. When I tried to remove the one with "Extend blabla" (?) next to it, it said it couldn't find the files to do it and offered a removal of the related entry. When I wanted to re-run the installer, it said "the framework itself or a higher version is already installed" and stalled)