500.21 Bad module “ManagedPipelineHandler” in its module list

Please follow these steps:

1) Run the command prompt as administrator.

2) Type either of the two lines below in the command prompt:

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

or

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i