Over the last month or two, my PC has frozen, not crashed, just frozen, while I was watching youtube. I have left it for a few hours, but it does not unfreeze. I am forced to hard restart the PC. When I restart Firefox, the first thing it does is update. It only happens when I have a Youtube video running, Youtube can be open in a tab but not running a video with no issue. Is it possible that the update request is locking up my PC? Is it being caused by Youtube? Any suggestions on how to stop it happening short of changing browsers? No error messages. No crash report. Nothing in the reports file to point me in the right direction.