I cannot activate the Notifications Center icon

Hello, everybody:
Today I've working in upgrade an old PC. From de 1703 version to 1903 and finally, to the 1909 version. All via Windows Update.
But when Igo to see the Notifications Center Icon, isn't there.
Searchin' for (regedit) for the key "DisableNotificationsCenter", I've change the "1" for the "o" ones. Reboot the machine and all still the same. In the Configuration, the icon appears greyed. And I don't know how can to resolve this trouble.
Thanks you all, in advance, por your help.
The Windows version is the latest Windows Pro x64 + Upgrade the kb today.

I've solved the trouble because these actions in Registry Editor (regedit):

1. Browse to: HKEY_USER\Software\Policies\Microsoft\Windows\Explorer.
Once there, look for DWORD named DisableNotificationCenter. Then, erase this DWORD.

2. Now, browse to: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Explorer.
Once there, look if exits DWORD named DisableNotificationCenter. Then, erase this DWORD.

3. Reboot the machine "et voilà", the Actions Center appears.

This solution goes by Enrique Cortés, from the Windows Community.
I think that this trouble is created for these DWORD leftover by Windows Update.

Thanks, anyway to everybody, and I hope this can support to others members with the same trouble.