I have installed Ubuntu 10.10 in my system. My system consist of : Pentium III, / M.B.: CUSL2 Asus / 512 MB RAM. When I upgraded online through Terminal Commands, it was upgraded to Ubuntu 11.04. On restarting the system just gives intimation warning as under: "It seems that you do not have the hardware required to run Unity. Please choose Ubuntu Classic at the login screen and you will be using the traditional environment" At this stage, the screen/system just hangs and doesen't proceed any further. How to get Login Screen and Choose Ubuntu Classic? Could anybody guide me and Help?
If your desktop is completely stuck, you can press alt+ctrl+f1, which will present you with a text login. Enter your username and password, and enter the following command: killall gnome-session. That should bring you back to the login screen. If it doesn't, try: killall -9 gnome-session. Only use the latter if the former doesn't work. That way, you're logged out cleanly.
Once you're at the login screen, select your user, but don't log in. At the bottom of your screen, you will see something called Sessions. Click it and select Ubuntu Classic. This will present you with the shell used in previous versions of Ubuntu, and that should work. I'll also mention that in 11.10, we have Unity 2D which is almost as good as Unity, but better suited for older hardware.