"My whole system to the extent it takes 5 to 10 minutes to get it to reboot!!" Oh!! I'm so sad to read this... But if you uninstall Firefox the problem persist? The fact that your whole system reboot in so long time can have many causes like this: - an unfinished update; - unsaved work - applications that desperately need you to confirm a close or a Save as dialog -running applications in background; -many applications at start- up; - an antivirus at start-up - a relative old installation of windows may need a defrag, a memory optimization, a refresh install - a relatively old computer that need an upgrade. And many, many causes... The first thing: try to uninstall Firefox and try to reboot IF the problem persist give us more information. Have a good day!

Distancetherapy said

My whole system to the extent it takes 5 to 10 minutes to get it to reboot!! I've been using Firefox for years, and had on and off problems with freezing, but this is far and away the worst. It's been so difficult to reboot, I've had to loosen the power cord to turn the system off. Also, the freeze has been so ubiquitous, I sometimes cannot reactivate the system from power save.. the monitor does not go back on. I have deactivated all plugins and extensions.. Please Help! I don't want to have to uninstall Firefox!! PS.. I can't rule out this is not due to Thunderbird as several programs freeze up at once.

Could you test in Firefox's Safe Mode? In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Hello, What is your Operating System? Try to optimize it! You could use CCleaner or Glarry Utility. You have Windows 10 and was installed an year ago? Back-up your documents and your important data and try a fresh install All was working fine few week ago? Try to restore your computer to the earlier time. How to do that See my other answer here: https://support.mozilla.org/en-US/questions/1235945 Hope this help!