I had a problem running an ASP.NET application (application Pool v4.0) on windows server 2008 IIS 7.5. I figured out that it's a permissions problem, but I couldn't find ASP.NET user group, so I granted NETWORK SERVICE and still it didn't work until I granted IIS_USERS permission to read/write and modify then it worked.
Why I can't find ASP.NET user group? and how can I add it if possible?