The short problem is that Debian starts as usual, but right before it clears the screen and shows the login information, there is an error (that I can't see, because it clears the screen immediately after), and then instead of switching to the graphical login manager, it leaves the system in text mode and I have to login through the text mode. If I use the command "startx", it starts up XFCE and everything is fine, just trying to figure out why the graphical login stopped showing up.

Some background information.... I upgraded my system from Debian Squeeze to Debian Wheezy yesterday, and I believe that the install went fine, and I was able to reboot, and the login window came up as usual at first, but then I was attempting to get Thunderbird to work, and it required the use of the multilib repo. I also installed ia32-libs and ia32-libs-gtk. I gave up on getting Thunderbird to work, and started using Icedove. When I rebooted, the X window wasn't working at all. After some googling, I found out that it may be a problem with the files in /etc/vga, and messed around with those files and that directory. I also reinstalled both the ia32-libs and ia32-libs-gtk packages, because I think that I may have purged them when I gave up on Thunderbird. I am still not sure if the ia32-libs and ia32-libs-gtk packages are needed or recommended to have installed....

Not sure if it's related, but at first, I would issue the "startx" command, it would seemingly just hang forever, and I eventually found out it was a problem with the .Xauthority file being owned by root. Once I changed the ownership to my user, "startx" works immediately.

I have checked the boot, dmesg, and boot.messages logs and there does not appear to be any warnings or errors occurring.

Please & thank you for any assistance!

Some additional information, it looks like gdm is/was being used for the display manager. It appears that gdm is marked as "deinstall" using dpkg. /etc/X11/default-display-manager has the display manager listed as "/usr/sbin/gdm", but this file does not exist. I looked at what was required for gdm3, and it looked like it was going into install a bunch of Gnome stuff, which I want to avoid as I'm running XFCE. Would it be safe to install SLiM? If it is safe, how would I go about installing it in Debian?

I installed SLiM and it seems to be working now. Seems like it was just a problem with the removal of gdm. It looks like gdm is outdated on Debian Wheezy, so I'm guessing... that Debian tried to remove gdm, and install gdm3, but gdm3 wasn't installed as gdm wasn't completely uninstalled? Anyways, SLiM is working like a champ!