Also worth checking the bios version level and seeing if the vendor has a newer bios version.
The readme notes should hopefully reveal if any newer version fixed crashes and freezes.
Or mnemonically - R eboot; E ven; I f; S ystem; U tterly; B roken.
This is the Sys Req key: NOTE: There exists less radical way than rebooting the whole system. NOTE: You should explicitly enable these key combinations.
When I try to create a pull request on Git Hub for one of the private repositories I contribute to, Firefox hangs and crashes badly enough that I need to kill the process or wait several minutes for the page to respond again.
I am currently on Ubuntu 16.04 and using Firefox Developer Edition (64-bit).
If even that doesn't work, you'll just have to R: Switch to XLATE mode E: Send Terminate signal to all processes except for init I: Send Kill signal to all processes except for init S: Sync all mounted file-systems U: Remount file-systems as read-only B: Reboot REISUB is BUSIER backwards, as in "The System is busier than it should be", if you need to remember it.
That will generally result in a dialog box saying that the program is not responding (but you already knew that) and presenting you with the option to kill the program or to continue to wait for it to respond. If you can't close a window by normal means, you can hit . Hover over the offending window and left-click to kill it.
Right clicking will cancel and return your mouse to normal.
Obviously you will not get Unity during testing this.
Graphics freezing can be one of/or a combination of the driver/compiz/X/kernel If you are willing to try any of the suggestions below first backup your system with a good backup tool such as Clone Zilla.
There are a small number of important fixes primarily in the 275 stable but a small number also in the 280beta that fixed freezes - it is worth a shot to see if these apply to your graphics card.