Forum Post: Re: Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel...'

1. From the Start menu, choose All Programs, and then choose Accessories.Right-click Command Prompt, and then choose Run as administrator.
2. At the command prompt, type the following command to change to the Microsoft.NET\Framework64\v4.0.30319 folder, and then press Enter.
   cd\Windows\Microsoft.NET\Framework64\v4.0.30319
3. At the command prompt, type the following command, and then press Enter.
   aspnet_regiis.exe -iru
4. At the command prompt, type the following command, and then press Enter.
   iisreset

This error can occur when there are multiple versions of the .NET Framework on the computer that is running IIS, and IIS was installed after .NET Framework 4.0 or before .NET 4.0 was registered.