I have Ubuntu 14.04. I got some updates today and after installing them restarted the pc. The mouse and keyboard don't work anymore. I was able to get them working when I got into BIOS. The mouse and keyboard both work on other BIOS. It just stopped working after the updates.
(I can't add comment to an answer, because of low rep) I'm the one that reported the bug a few days ago. You should click the button that say this bug affect me too to mark the bug as confirmed.
(Solution / Workarround) Like I said in the bug report, the previous kernel is working. By default, Ubuntu doesn't remove previous installed kernel. You can select the previous working kernel in grub (you may have to press escape to get the grub boot menu).