Ubuntu 12.10 shows no launcher or menu

I have 'upgraded' to Ubuntu 12.10 from a previous nice version that always worked. I have installed from a CD downloaded from this site. I start the PC (HP Pavillion zv5200) and arrive at a signon screen which has my username and "Guest". This screen shows the menu at the top with power, time, calendar, etc. So I enter my password and I am taken to a screen which only shows a wallpaper, nothing else. If I move the mouse and 'push' against the left limit I do not get a launcher app. Nothing. The only thing that works is opening a terminal (ctrl+alt+F1). I have tried several of the hot-key combinations I've read about on the site but none do anything, nothing happens. Can anyone help? Thanks very much!

Solution 1:

I had the same problem but none of the above worked for me. Uninstalling compizconfig-settings-manager also didn't work.

In the end I found the answer here, as I was seeing the same 'Fatal: glXQueryExtensionsString is NULL for screen 0' errors in a terminal when trying to start unity. I realised I was using a proprietary ATI display driver before I upgraded from 12.04 to 12.10. I issued the commands below in a terminal:

sudo add-apt-repository ppa:makson96/fglrx 
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install fglrx-legacy

and then rebooted my PC. Unity then reappeared when I logged in.

There's an explanation here of why the upgrade fails in the first place. I was using an AMD Mobility Radeon HD 3650 graphics card (ATI RV635). Use:

lspci | grep VGA

to find out what graphics card you are using.

Solution 2:

There are know issues with restricted video drivers, compiz, and/or unity 3D (one or all or maybe something else too). If the other answers that suggest reseting compiz and unity don't work, try running unity 2D. At the login screen, right click the Ubuntu circle thing to the right of your name, click Ubuntu 2D, and login as normal.