Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel' after WCF non-http activation in IIS 7.5 with .Net 4.0

"Could not load type 'System.ServiceModel.Activation.HttpModule' from assembly 'System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

This is an error you may encounter when you configure your machine ie IIS 7.5 for non-http activation to host WCF services.Initially I wonder what I did to reach this situation.But soon I realized that the relation between IIS and .Net 4.0 has broken and I need to register .Net 4.0 to IIS. Just used the famous aspnet_regiis.exe utility which is located at <%WindowsDir%>\Microsoft.NET\Framework\v4.0.30319.

Mainly this happens when we install .Net framework 4.0 after IIS installation or activating non http wcf service support after IIS and .Net 4.0 installations.