In an ASP.NET application can we add more than one WEB.CONFIG files? Can it run?

Yes we can add more than one Web.Config files for each folder in ASP.net. When we define the web.config for the folder then this will be applicable for the applications in the folder. At the same time if we define the web.config for the applications in the sub folder then it will be applicable for the sub folder applications. So any sub folder application derives it properties from the folder application web.config and if some of the parameters are override in the sub folder application then the sub folder application will take the its own web.config parameters. For the entire application there can be only one main Web.Config. If you assign membership and roles to an application you can see a specific web.config will get created for the folder.