I have installed a few USB drivers, but Android Studio Sorry, I should have explained in more details.


In my mobile, Gear icon -> Settings -> SYSTEM -> {} Developer options, I have select (set tick) both "Android debugging" and "USB debugging notify".
After plug in my mobile to my PC with a USB cable, from my PC I can see the files in my mobile, I can even move the files between my PC and my mobile.
In my PC, run Android Studio/bin/studio.exe, in the Android Studio 2.1.1 window, I click the run icon, "Select Deployment Target" window shows with message "No USB devices or running emulators detected".
People said I need Google USB Driver. I then downloaded it. After that, In Android Studio 2.1.1 window -> Tools -> Android -> SDK Manager -> "Default Settings" -> SDK Tools, I have found "Google USB Driver 11 Installed".
However, I have still got "No USB devices or running emulators detected" when I run Android Studio.


That is why I want to know all USB Drivers installed in my computer, which USB Driver my computer is using and most important, what USB Driver my Android Studio is using?

If you know what I am doing wrong, please give me your suggestion so that I can use the Android Studio + my mobile to make a very simple app.

Thanks a lot for your helps!
Under some circumstances the ADB server does not recognize new devices. In such a case you can restart it from command-line by executing adb kill-server. The next time Android Studio tries to enumerate the available devices the ADB server will be started automatically. 

If that does not help you should check the device manager if you see the ADB device driver of your smartphone.

For Android USB debugging with Windows you need the ADB USB driver for the ADB sub-device. Usually the driver itself is the same for all devices, however Windows does not know this as the drivers provided by Google only contain the device IDs of the Nexus devices. 

If you don't mind editing driver configuration files you can add your device-id manually:

Android device not seen by ADB but accessible from Windows
Note that you have to adapt the USB IDs using the vendor and device ID of your Android device (shown in the Windows device manager).

BTW: "Google USB Driver 11 Installed" means you have downloaded and extracted the Google drivers, but not that they are automatically used by Windows. 

Usually the best approach is to search for the ADB driver for your device on the manufacturer homepage.