Could you check your history on where you got the problem download?

Then try downloading from this page instead (scroll down to your preferred language):

https://www.mozilla.org/firefox/all/

Also, if the old Firefox is still installed, could you test in Firefox's Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is not running: Hold down the Shift key when starting Firefox.

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

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• 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 less crashy?

If you got the Mozilla Crash Reporter dialog, your Firefox may have logged some data that would help track down the cause of the problem. You can submit that data to Mozilla and share it with forum volunteers to see whether it points to the solution. Please check the last section of the support article "Firefox Crashes" for steps to get those crash IDs from the about:crashes page, and then post some of the recent ones here.

CHALLY1950 said

MOZILLA CRASHED, WHEN I TRY TO DOWNLOAD MY SPY WARE SAYS COUPONARIFIC IS ATTACHED

Good day. If you download from a third-party resource , most likely it is even normal. BUT when downloading from the official website , it is unlikely you set something apart browser.