Comment 2 for bug 163508

As commented by jtholmes attach the following information so that we can help you better
~/.xsession-errors
/var/log/Xorg.0.log
Also tell us whether you are using the default drivers or the restricted ones? If you are using the latter then have you tried disabling them and reproducing the error?
kindly attach your kernel version too by using the command uname -a in the terminal and pasting the output here.