I have a web site published to a Windows 2008 R2 server running IIS 7.5. The web site accesses a SQL 2008 database on a different server.

The web site is accessed from an intranet.

In global.aspx users are logged in by retrieving their Windows.Identity which is passed to a stored procedure that checks they have rights to access the system. All the people trying to access the system have rights to the system and if I run the stored procedure with their various Windows.Identities passed as the parameter - it returns that they are authorized.

I have admin rights on the web server. If I browse the site from my box it works okay. If another user who has admin rights on the server browses the site (at the same time as me - or on their own) it works okay.

If someone without admin rights to the server browses the site - and they are the only person 'on' the site - it works okay. If a second person tries to browse the site at the same time as the first person is logged in ... nothing happens. The progress bar in the browser just sits there forever. No errors etc.

So, no-one using the site ... Fred types http://server1/system1/ into his browser and the site works okay.

Jim types http://server1/system1/ into his browser and nothing happens.

Fred logs off and Jim tries the site again. Works fine for Jim this time.

Any ideas? I'm baffled.

Thanks for any help.