Its been like 5-7 days I am facing this problem since my last Kernel update. The problem was my screen kept freezing, keyboard did not work, mouse moved but clicks did not work.
Today got some time and found that the problem has been reported as a bug but it has not been assigned to anyone.
So i went over to google and found a forum topic for the same and found a work around. Since the problem is the kernel version 3.5.0-26. you can check your version with following command.
Fireup the terminal and type
$ uname -r
you should be able to something like this below
since mine is 3.5.0-26 and changed it to older one.
When your system starts to boot press SHIFT (keep pressing it), until you see boot options screen
From the list choose 3.5.0-25-generic (without recovery mode) and press ‘Enter’.