IIS Fails with error "App-Domain could not be created"

Getting the error "Failed to execute request because the App-Domain could not be created." can be fixed by doing the following to "re" register ASP with IIS. Other descriptions of this error can be

• Error: 0x80131902
• Failed to initialize the AppDomain:/LM/W3SVC/1/ROOT
• Exception: System.Configuration.ConfigurationErrorsException

You probably have the latest version of .NET in the location  C:\Windows\Microsoft.Net\Framework\ but make sure of this first. First Stop Web Services by typing the following at the command prompt: 

net stop w3svc

Uninstall all instances of ASP.NET by running the following command: 

aspnet_regiis.exe -ua

You are now ready to re-install ASP.NET to IIS with the following:

aspnet_regiis.exe -i

Lastly you need to start up the webserver:

net start w3svc

Hope this helps!