I run HP laptop Pavilion with processor S7 and Intel Graphic card hd 520. Just bought this laptop about 3 months ago.
After upgrading from 14.04 to 16.04 and rebooting, I got flashing screen between graphic mode and text continually.
After reading some of the answers I logged through command line and attempted to execute command which some suggested solve their problem.
They said do this.
sudo apt get-update (enter password when prompted)
sudo apt get-install xserver-xorg-video-intel
reboot
After typing first line I got another problem.
relocation error relocation error /usr/lib/x86_64-linux-gnu/libapt-pkg.so.5.0: symbol ZNK..... in file libstdc++.so.6 with link time reference
Any suggestion? Be gentle with me, this is my first computer with Ubuntu.
As a note, when I run installation to try out without installing from the CD for 16.04 I get into desktop, no problems with drivers.
I have option to install fresh install but this would cause me a lot of work to recreate what I had already and it is possible that I would be faced with the same problem after that.