This morning I tried to install amd drivers on my 14.04 lts ubuntu. It rebooted to a blank screen and nothing I was doing in recovery mode fixed it. (Uninstalling fglrx-* etc) Then I unwisely followed a tutorial which told me to uninstall and reinstall xserver-xorg, it wouldn't reinstall without errors so in desperation I burnt a new live cd and used the upgrade option in the install to reinstall to 14.04 hoping to avoid data loss.
Now I get to the login screen and my keyboard and mouse stop working. They work before this in bios and the grub menu, but not in recovery mode either.
Other people have had similar problems but recovery mode is working for them so they can resolve it from there but there's nothing out of my mouse/keyboard after grub menu.