If you cannot start debugging on web server, cannot open application on IIS at all, have any problems with managed integrated handler or similar when accessing application, then you need to install .NET 4.0 on server. Easiest way is using Web Platform Installer, under Frameworks.
If .NET 4.0 is already installed, then you need to open cmd as Administrator, and run “%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i”
That solved problems for me.