Please make sure you have nvidia driver 304.43 installed on your system, it should solve the issue for you. The problem you are facing is not in Unity I would say.
** Changed in: unity (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1063046 Title: The whole system hanged and stop responding. Had to reboot and lost unsaved data To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1063046/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs