These apply if it won't boot into failsafe Gnome either:
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My first guess:
If it just makes the groovy login music and hangs with a brown bg or shows the starting up window and hangs, it could be due to the date bug.
Log in as you or root to failsafe terminal.
type date and see if it's correct.
If it's not and you're logged on as you, type sudo date mmddhhmmyyyy
enter your password
ex:
for June 27 2006 at 10:12 PM, you would type 062722122006 (use 24-hour time for the year)
If you're logged on as root, omit the sudo.
type date to see if it worked.
type exit to get to the log-in screen.
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My second guess
I don't think this is what's happening, but here is what sometimes happens in similar situations. Usually, it will just give you an error.
During setup, did you create another account? You can't log into Gnome with the root account. If you need to make an account:
Log on with your root account with the session set to failsafe terminal.
Type useradd once it has loaded and follow the steps.
Type exit to get back to the logon screen.
Logon with the user you created.
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Maybe one of those will work,
J.S.