I had installed 12.10 on my lenovo ideapad z560 laptop at work last week. I use it together with an external monitor and everything was working fine and then today I upgraded the distribution to 13.04. Now when I plug in the external monitor, after a while the display on both screens freeze (seemingly) randomly. I did a google search and found this. I also tried the suggestion given in comment#14 on that link, which is basically adding this ppa to the repositories list and installing the packages in it. But when I checked on synaptic, no packages of the name xserver-xorg-input-evdev_126.96.36.1991-1ubuntu3 were included.
Another comment on the first link I provided said it might be related to chromium, but I verified that this also happened when I was using firefox instead.
I cannot seem to find any other fixes, so I'm stuck at this point. Any suggestions will be appreciated.