apt-get upgrade: now I can not login at ALL!!!help

[Jose M de Aguiar <jmaguiar@surfree.com>]

Help!!!!!

I have my Debian kernel 2.2.14. Today, as I periodically do, I run
apt-get update
then apt-get upgrade. During the process I answered ALL QUESTIONS WITH
KEEPING THE INSTALLED CONFIGURATION.(Default=N) . Once finished the
upgrade, I was not able to use Real Audio. My default windows manager
was
fvwm95. I restarted the windows manager and doing a login in Debian, as
usual.
But the windows manager was twm. I DID NOT MAKE ANY CHANGES AT ALL
DURING UPGRADE!!!

I decided to reboot the machine. It did go well, however once xdm starts
now I
don't have the Debian Login Window. Instead, now it comes XWindow.
But the worst is: I CAN NOT LOGIN AS USER OR ROOT. It is really serious.

Something is NOT WORKING IN THE DEBIAN PACKAGE.

WHAT CAN I DO?????? HOW CAN I RESCUE MY SYSTEM AND FIX IT?

Please, URGENT reply to: jmaguiar@surfree.com

Thanks a lot!!!