It may be a dependent package. If software update failed. Then you can try it with terminal. Open a terminal by pressing Ctrl+alt+t.
Type or copy/paste with mouse or keyboard. You can paste into terminal by pressing Ctrl+shift+v.
sudo apt-get clean to clean previous software cache. Remember you have to provide your password when promoted. Password field will stay blank when you enter password....don't worry about it. Just enter password and press enter
sudo apt-get -f install to solve any dependency problem.
sudo apt-get update && sudo apt-get upgrade to update your softwarelist and upgrade all software component that have a new version available.
upgrade command your kernel will not upgrade. So you have to type
sudo apt-get dist-upgrade.