K I have resisted it for months, but the urge finally got the best of me. I hit the upgrade button that was in the task bar, let it do it's thing and restarted the machine. BOOM itsa dead machine! Sad
If I had to guess I would say that you did a system upgrade with the testing repository enabled. ( I wish there was a warning that popped up for that kind of thing)
Sound like kdm has highjacked top spot as your Display Manager. I'm assuming you were using VL-6.0 standard and GDM was your display manager and XFCE was your desktop environment before this all happened.
The first step would be to get you back to the gdm login screen. Start your machine in TUI mode and set yourself up as a root user. In the terminal type...
Eleven lines down there is a line that reads...DISPLAY_MANAGER=KDM
Change it to read.... DISPLAY_MANAGER=GDM
Then ctrl +X and 'Y' (for yes) to save your changes.
Type 'init 6' in the terminal while still root, this will restart your machine. Hopefully, you will now see the familiar GDM Display manager.
You should still be able to launch into XFCE from the kdm Display Manager. You just need to reselect it as your session from the KDM menu.
This is only a fix for KDM hijacking the display manager top spot. If your troubles run deeper, let us know.