Comment 5 for bug 156429

1. run system in recovery mode
2. write command :
mcedit /etc/X11/xorg.conf

(if there is no mcedit instal mc by : apt-get install mc)

3.find line :
Driver "radeon" (or "ati")
change "radeon" or "ati" to "vga"
4. write command :
init 5

5. paste here xorg.conf :) and /var/log/Xorg.log (all as attachment - long files)

:)