Glad you got it sorted out, some days technology can be a real struggle but you struggled through and prevailed in the end.
Still think there must be something not quite right with your .NET installation since this should not be needed in Web.config. I'm pretty sure stuff like that is supposed to be in machine.config in .NET 4 so it isn't typically needed in web.config. This was one of the changes in .NET 4 whereas back in .NET 3.5 we had to have those things in web.config, in .NET 4 they moved that stuff to machine.config and we cannot usually have it in Web.config because it causes an error if it is in both places. So your machine seems to somehow not have that in machine.config.
I think sometimes things go wrong when .NET is installed before IIS is installed, sometimes not everything gets wired up correctly when IIS is added later. If IIS is installed first then things usually get wired up correctly for ASP.NET by the .NET installation but if done the other way it doesn't always. Anyway that is one theory of how some machines don't work as expected for ASP.NET.