After the 4th install of FC 4, I can finally log in - but only as root.
On the login screen, if I enter the incorrect password, lettering on the screen changes to indicate an incorrect login, as might be expected. Using the correct password, a separate dialog box appears saying "Authentication Failed". The root name and password is the only combination that works.
Booting with selinux=0 on the Grub command line does not help.
When installing, I enabled / selected kerberos and LDAP, thinking I might want them in the future - I did not configure them. Do I have to reinstall without them?