Closing browser doesn't terminate sessions. Even if you terminate all sessions IIS will not unload DLL module until you manually do this.
Another question, why my dll file work in virtual folder, but it doesn't work in the main floder(C:\Inetpub\wwwroot\Project33.dll), why?
IIS doesn't allow this.
Another question, can we throw off it's the name of the file dll?(I set it by default for visit, but it doesn't work) so we can visit by www.exemple.com
Shown as picture2:
For this you need some URL rewriting. I don't know the details but you can search web for IIS and URL rewriting.