I have been trying to run MyUnity, and it's been working fine until today, when it comes up with the message:
So, apparently I am running Unity-2D. So I did a little command-line search withecho $DESKTOP_SESSION
and sure enough, it spat out simply "ubuntu-2d".
I have been using Ubuntu Tweak and perhaps I did something stupid in there, but I don't think it even had a feature like that. I've also noticed the clear differences in Ubuntu 2D to Ubuntu 3D, as well.
I have 12.04 Ubuntu. So is it possible for me to "revert" back to Ubuntu/Unity 3D?
Edit: My graphic card is a 2GB dedicated AMD Radeon HD 7750, which I've come to think needs to be upgraded 12.6 version. I'll try this and let you know the of the outcome, thanks so much for helping.
Result: after successfully updating the graphics card, I now can run 3D. Thanks so much to all of you and I'm sorry for such an unusual question!