I have no idea, but the error indicates you are running .NET 4.0 which is just a community preview not an official release.
Information: Microsoft .NET Framework Version:4.0.20506; ASP.NET Version:4.0.20506.1
First thing I would try is uninstalling .NET 4.0, but then I would not have installed that in the first place on my main machine, too risky. I have no idea if uninstalling it will solve the problem or not but it seems your machine is pretty well hosed at this point so thats what I would try.
Hope it helps,
Joe