i've installed ubuntu 14.04 on my old notebook (acer travelmate 2420). everything is fine except the shutdown. it's hanging in the last screen ("ubuntu" with the points beneath - they change their colour properly...as long as i don't press the "on/off" button of the notebook). i've changed this line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" into this: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=force" doesn't work. can anybody help? i'm a ubuntu beginner, so i maybe don't understand too specific things. thank you.