I have a Windows 2K3 server (standard) running Exchange 2003. I have OWA working fine on this box (all one server).
If we reboot the server then the IIS settings reset to incorporate IWA (Integrated Windows Auth) and sets the defauly domian to be "\". We don't want or need this. User then have to log in using "domain\username" or "username@domain". We have to take off IWA and set the default domain to be "domain". Do an iisreset from cmd and hey hey it works.
The reboot also resets our OWA spell checker and we have to reset the IWA on the /Exchweb Vir Dir.
Its a reall pain because some of our techs never remeber to change the settings back!