How to migrate IIS6 web.config to IIS7

If you are using custom httpHandlers or httpModules, you would need to
run the migration command below.

C:\> %systemroot%\system32\inetsrv\APPCMD.EXE migrate config "domain_name.com/virtual_directory"
Successfully migrated section "system.web/httpModules".
Successfully migrated section "system.web/httpHandlers".

Now if you are going to migate the web.config inside the WEB_ROOT directory itself and not inside any virtual directory don’t miss a forward slash, / after the domain name.

eg:

C:\> %systemroot%\system32\inetsrv\APPCMD.EXE migrate config "domain_name.com/"
Successfully migrated section "system.web/httpModules".
Successfully migrated section "system.web/httpHandlers".

Otherwise you may get an error like below,

ERROR ( message:Cannot find APP object with identifier “domainame.com”. )

A good article to refer is available at http://blogs.msdn.com/tmarq/archive/2007/08/30/iis-7-0-asp-net-pipelines-modules-handlers-and-preconditions.aspx