ASP.NET IIS Errors troubleshooting

If you have this kind of error when you tried to run your ASP.NET app on IIS

HTTP Error 403.14 - Forbidden

The Web server is configured to not list the contents of this directory.

or this:

HTTP Error 500.21 - Internal Server Error

Handler "BlockViewHandler" has a bad module "ManagedPipelineHandler" in its module list

just do this:

Windows Logo > Run

type this:

cmd.exe

then press:

Ctrl+Shift+Enter

that shortcut key triggers running cmd.exe with an Administrator rights

then type this on terminal:

%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis.exe -i