Help! Red hat doesn't recognize any usernames!

[Anne Moore]

Hi All,

My server crashed. Now when I boot it up, just about all services/daemons
that depend on any username, won't start because it doesn't recognize the
username. I can also no longer logon as root or any other username because
Red Hat doesn't recognize that the "user exists." 

Does anyone have any ideas on how to troubleshoot or fix this very odd
issue? My entire server is down because of it, which means 450 people can
not logon to my network.

I've fixed the file system, and now it has no errors. The Haldaemon won't
start, nor the message bus, or atd, or many others.

Thank you for your help!

Anne