windows testing is standalone testing only the real users will work on the application here the client-server are both at same place
where as web testing is working on web applications so simply every user should be a virtual user bcoz client and server are not at same place.For this web applications we need to check mainly performence test .
Web based application is for multi user application.There is two types of web sites one is Intranet site and second is Internet site for ex. Vodafone site.
Window based application is for single user only. At a time single user can use this application for example Outlook.