Inbuilt and external main apps crashing no matter what.

hi,
messages, gmail, google chrome, google search, and a few other apps keep closing on my samsung c9. have tried all the possible solutions on the internet but to no avail.
can't open messages which came preinstalled, at all. it is the same with a few other apps which came preinstalled and some which i installed later.
can't use the google search engine or any other for that matter either. removed my google/ gmail accounts from my fone too and uninstalled recent app updates as well.
now when i try to add a google account from the settings, it goes into 'checking info' and then the blue circle and all disappears into blackness, nothing but blackness. and then, nothing happens. can't go back on the black screen and then have to forcibly close it. can't go into google playstore either and when i go into it from a webpage it says 'this device is not registered'.
the phone's software got updated on 24th sep'18. all was fine till then and then these main apps crashed.
please help.
thank you in advance.
priya.

Welcome to Android Central! Does it work if you boot into Safe Mode? https://www.hardreset.info/devices/s...faq/safe-mode/

Originally Posted by B. Diddy

Welcome to Android Central! Does it work if you boot into Safe Mode? https://www.hardreset.info/devices/s...faq/safe-mode/

Hi.
Thanks for the link and tried the same. Sadly, the problem remains unchanged.
What else could be done?

Try using Smart Switch to reinstall the firmware: http://www.sammobile.com/forum/showthread.php?t=29914

Hi,
Thanks again for the link. Followed the guide, but the problem remained. The software update had happened on 23rd sep'18 so there was no further development. Backed-up with smart switch.
Finally gave up and resorted to 'factory reset'. Then restored.
With all the setting up like that of a new phone, have finally heaved a sigh of relief.
Thank you so much, nonetheless, for your guidance.
Regards.
Priya.