From time to time firefox cause to my Ubuntu machine to stuck.(nothing run on the machine except firefox) I cant move the mouse or move windows by keyboard. In some cases i have wait for a few minutes and than close last open tab in firefox and it solve the problem in other cases i do restart. Is there any way to prevent it, limit forefox in some way? In windows in most cased even with 100% cpu you can do alt-ctrl-delete and get the task manager, is there a top priority combination in linux that give you terminal? Or any other way ... Run on Ubuntux86 with GNOME , 2GB RAM, dual core cpu