Ubuntu 16.04 Desktop Freeze

currently I've installed on my Lenovo G50-30 Ubuntu 16.04 64bit. Now I got after the system is running for a short or a longer time desktop freezes. As desktop software I use Unity, also tried Xfce -> same problem.

Also the RAM was changed and no improvement was able to be seen. Could you please give me some ideas were the root cause could be?

my system:

Linux jon-Lenovo-G50-30 4.4.0-22-generic #39-Ubuntu SMP Thu May 5 16:53:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

I run into the same problem this morning. Ubuntu 16.04 LTS on a DELL Latitude E5450 and could fix the problem as follows:

Get into GRUB menu while holding ESC key on startup. When GRUB menu appears, I've pressed "e" to change the boot options. I added "nosetmode" as described here: How do I set 'nomodeset' after I've already installed Ubuntu?

Afterwards I could boot and get a terminal prompt (no GUI). In the /var/log/syslog I found problems regarding to gdm3 (gnome). I removed it and erverything works fine.

Quick fix: Remove gdm3 and gnome if installed afterwards.