Try to select at the loginscreen Unity 2D (this is done via the little 'radar-icon' nearby your login name (the one were you type in your name and password)
If this loads correct, you can adjust some things so Unity 3D loads properly. I suspect the Steam-program got a little bit in the way with something. (This you have to test over and over again)
If Unity 2D doesn't load:
Can you start up in recovery mode ?
- To achieve this simply open up Grub (after Bios-screen press and hold SHIFT) and select the recovery modus. From there on you can try to initialise Unity again.
We need a bit more information, I see you've installed Steam is that program shut down correctly before you quited Ubuntu ?
Apparently it's clear that Unity doesn't load fully; so if tweaks were made (e.g. CCSM used) it could be they are in the way of things.
ATI HD 6850
Intel Core 2 Duo E8400 3GHz
6 GB of RAM
Asus P5K PRO – Kossak Feb 17 '13 at 12:26
sudo apt-get install linux-headers-generic
– Chris Carter Feb 17 '13 at 12:43I also found solution for invisible taskbar in Unity 3D, thank you all for help. This is the magic that solved my problem (that Unity 3D desktop wasn't showing up properly): I wrote these commands in terminal, one at a time: "sudo apt-get purge fglrx lightdm" "sudo apt-get install lightdm ubuntu-desktop" – Kossak Feb 17 '13 at 15:38