Some entries in your submitted crash report indicate this may be related to either Websense, Norton or Symantec Endpoint Protection security software. If you run it, can you see if these questions are of any help?
one, two, three
However, you seem to be using Firefox 51.0.1, so the issue may have been resolved in an updated version. Considering your system’s microcode however, I’m afraid it won’t be able to run higher versions than 56, which you may be aware of, unless you kept the older version for other reasons. Your best bet would therefor be to upgrade it to Firefox 52 ESR.
Unrelated: you seem to have a Standard VGA Graphics Adapter graphics driver installed. Perhaps you may achieve better results / performance by installing a suitable driver for your graphics card (Intel HD Graphics 4600?).
Some entries in your [https://crash-stats.mozilla.com/report/index/1ee76b41-282c-4837-aad3-261610180302 submitted crash report] indicate this may be related to either Websense, Norton or Symantec Endpoint Protection security software. If you run it, can you see if these questions are of any help?
[/questions/1134317 one], [/questions/1152205 two], [/questions/1126306 three]
However, you seem to be using Firefox 51.0.1, so the issue may have been resolved in an updated version. Considering your system’s [[Crash on Broadwell-U with old microcode|microcode]] however, I’m afraid it won’t be able to run higher versions than 56, which you may be aware of, unless you kept the older version for other reasons. Your best bet would therefor be to upgrade it to [[Switch to Firefox Extended Support Release (ESR) for personal use|Firefox 52 ESR]].
Unrelated: you seem to have a Standard VGA Graphics Adapter graphics driver installed. Perhaps you may achieve better results / performance by installing a suitable driver for your graphics card ([https://downloadcenter.intel.com/search?keyword=Intel+HD+Graphics+4600 Intel HD Graphics 4600]?).