http://askubuntu.com – Writing this from an older Dell Notebook, ugpraded to 12.04 32-Bit, which works well. My more modern Dell Notebook worked well for 1/2 day after upgrading to 12.04 64-Bit, now I'm having problems logging in: System boots normally, (Unity) can enter my password, the login-screen reports 'Logging in....', but that's the end, won't log in even after 30 minutes - it just stays on the login screen. (HowTos)