When Ubuntu 14.04 or 14.10 comes back from sleep or suspend mode, the keyboard and mouse freeze. You can't click or enter anything.
This forces you to shut the system down using the power button. This issue normally starts after a kernel upgrade.
The solution is to reinstall xserver. Open terminal by pressing CTRL-ALT-T and type or copy and paste the code bellow.
sudo apt-get install --reinstall xserver-xorg-input-all
Edited by NickAu, 11 March 2015 - 03:01 PM.