I wanted to install skype, so i followed the instructions on this site :
and because i have an amd64, i installed the i386 files and i386 libraries
libdbus-1.3, libqt4-core, libqt4-gui,
skype worked nicely!
but i closed skype and continued using my ubuntu, but then i tried to open vlc, but it didnt want to open, and i felt ubuntu having a bad time, so i went to a console: ctrl+alt+F1, typed /etc/init.d/gdm stop and then /etc/init.d/gdm start and it said that gdm display manager failed.
tried rebooting, it did the same.
tried ldconfig as root, but still the same.
Any help ???!