Dot Net Framework issues!

I've been trying to install dotNet Framework 3.5 SP1 on my laptop recently, but with no luck at all..

I have my laptop running for more than 2 years, and I managed to survive major Virus attacks, and all kinds of performance problems with continuous tweaking and determination to avoid formatting and re-installation of everything! I just refuse to be defeated by a Virus or some OS failures :)

anyways, during my searches, I bumped to this site, and this tool which "resets" the status of my different dot net Frameworks, enabling 3.5 SP1 to be installed on a clean ground!

I only cleaned up 3.5 and 3.0 Frameworks, then.. Everything went fine!

I wonder why doesn't MS release such things, or embed it in the tools instead of the useless apologize messages!

here is the link:
http://blogs.msdn.com/astebner/archive/2006/05/30/611355.aspx