People who have large solution with lot of differents projects type (BizTalk, c# WCF….) may want to disable the debugging webserver, when they enter in debug mode.
On the web you can find lot of solution like updating regiter key or delete web debug server.
But the simpliest technic is to disable the project to start the debug asp server :
Click on the project, then go to the property tab and set to false the property « Always Start When debugging » :