OK, I just discovered that the .NET does not appear in my installed programs but when I launched the setup for 4.5, it said it could not be installed because it already was installed. There's only 1 folder (called RedistList) in the Microsoft.NET folder with two xml files. I'm gonna check that with Microsoft.
I'm on Windows 8.
.Net 4.5 is default on Windows 8.
I don't have windows 8 installed so I can't debug it there unfortunately.
But if you know a bit of programming and have some time you can download VS express and play around with the source code.