ubuntu 12.4 once in a while my system freezes and have no way to get around the problem except manually restarting
I'm kind of new to ubuntu. i used ubuntu 4 years ago and return to windows, but now i wanted to start using ubuntu again and got a serious problem.
I have read every single post about system freezes, but cannot find my exact problem.
Basically, Ubuntu 11.10 is randomly freezing. When it happens, I cannot do anything, not even move the mouse. Everything is locked up, even the keyboard is not responding (num lock does nothing).