Yes, clean install help, but when I tried to remove it by registry (only for test) it removed permanently, so I uninstall the update of 19042.685 and install it again but Meet Now didn't come back, so I did clean install.
It's great everyone is helping you recover what you lost but before you start going crazy fixing stuff what you might want to do is check to see if you have a virus or some malware running in your computer. By your initial first question and the description of the problem it almost sounded like malicious activity to me.