Enable or Disable Cortana in Windows 10  

Brink said:

Check to see if you may have another policy enabled that could be preventing Cortana to search the web.

See Applied Group Policies in Windows 10 - Windows 10 General Tips Tutorials

The other question would be best asked in a new thread instead since it's not directly related to this tutorial.

Disabled and enabled GP list:

Brink said:

I don't see anything there that would disable Cortana. I assume that you don't have any "User Configuration" policies enabled/disabled.

Next thing to check is what region is your PC set to, and what language is Cortana set to? If these two don't match, it can cause Cortana to not always work.

Change Country or Region Home Location in Windows 10 - Windows 10 General Tips Tutorials

Change Cortana Language in Windows 10 - Windows 10 Apps Features Tutorials

"Country or Region" setting is set to U.S.
There is not "Cortana Language" (all settings in yellow border isn't there!). There is only "My Device History" and "SafeSearch".

Brink said:

It doesn't sound like you have the latest build of Windows 10 installed.

If you like, you might update to the latest non-Insider release build 15063.138 via Windows Update to see if that may help.

Cumulative Update KB4015583 Windows 10 v1703 Build 15063.138 - - Windows 10 Forums

Installed Update: Cumulative Update KB4015583 Windows 10 v1703 Build 15063.138
Current version after update installation [Screenshot]...

Anyway... Thanks Mr .::Brink::. :)

Brink said:

If you like as a test, set your region and Cortana language to English (United States), to see if it works afterwards.

There is no option to select "Cortana Language" in taskbar search box settings (the only settings that I can see and change, screenshot):

Is that possible to reinstall Cortana (with PowerShell or CMD command), without refresh or reinstall or reset all windows settings?

Brink said:

How about after setting your PC's region to US as a test?

Change Country or Region Home Location in Windows 10 - Windows 10 General Tips Tutorials

You could try the command for Cortana in Option Two of the tutorial below to reinstall and re-register it to see if that may help.

Reinstall and Re-register Apps in Windows 10 - Windows 10 Performance Maintenance Tutorials

Default PC's region is set to US, I didn't change it.
I reinstalled Cortana using this method: Reinstall Cortana on desktop Accidentally uninstalled app - Microsoft Community