Yes, I have tried to reinstall it also.

We're sorry to hear that your Firefox seems to be crashing when you open it. Please perform the following steps to give us a crash report ID that helps us find out more about the cause of the crash.

1. On the keyboard, press [Windows] The image "Windows key" does not exist. + [R]. This should bring up a Run window that contains a text field.
2. In that text field, type %APPDATA% and press Enter. An explorer window should open.
3. From that explorer window, double-click on the Mozilla folder, then double-click on Firefox and then on Crash reports. Double-click on submitted.
4. Now, you should see a list of files that contain reports. Go to View > Arrange Icons by > Modified to get the most recent files at the top of the window.
5. Open the most recent 5 files with a text editor and copy the IDs.
6. Paste each ID with bp- into the reply window on the forums.

Thanks in advance!

You can find more information and troubleshooting steps in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

I'm in the Crash Reports folder, but there appears to be no 'submitted' folder. Only 'events' and a bunch of files called 'InstallTime' with dates after 'InstallTime'.

What security software are you running? Are you running Windows Pro version? What happens under a different user account?

What do you mean security software? Mcafee? No, I am not. I am using Windows 10 Home. The same thing happens.

Did you already try disabling McAfee?