I just fixed this problem.
The problem was in the video driver: I have NVidia driver installed using *.run file. After updating the kernel the driver was not updated but xorg.conf file was still pointing to the NVidia driver which does not exist for the new kernel.
I reinstalled NVidia driver and everything works again.
---------- Post added at 10:01 PM CST ---------- Previous post was at 03:17 PM CST ----------
I just noticed that after I reinstall NVidia driver for the new kernel it was automatically uninstalled for the previous kernel
Does anybody have any suggestions how to install video driver which is valid for both kernel versions?