IT:AD:SharePoint:Issues:Installation Blows Out Other Sites

You have working websites, and then install SharePoint. Now all you your websites are showing an error similar to the following:

Could not load type 'System.ServiceModel.Activation.HttpModule' 
from assembly 'System.ServiceModel, Version=4.0.0.0, ...'.

Exception Details: System.TypeLoadException: 
Could not load type 'System.ServiceModel.Activation.HttpModule' 
from assembly 'System.ServiceModel, Version=4.0.0.0, ....'.

It appears SharePoint blew .NET40 out of IIS. Reregister it:

aspnet_regiis -iru

• http://bit.ly/zMhlmt
• http://support.microsoft.com/kb/2015129