Do let me know if this works for you :)
Hello I am back... I followed your instructions and the problem still existed. I uninstalled Firefox Quantum and ran CCleaner. Rebooted/reinstalled Firefox (64bit) and checked the settings you told me to and everything looked good from there. Opened Task Manager and walla it opened without hesitation. So I believe you did help to fix this issue. :dance:
Thank you so much!!