Link to Google's USB driver page:
The Google USB Driver is required to perform adb debugging on Windows with Google devices.
developer.android.com
Extract zip and right-click on win-usb file and choose 'Install'. Then when you plug in your device, it should pick up ADB driver automatically. For Fastboot, bootloader mode, you'll need to go into Device Manger, find the 'Android' device, update driver/pick from list/Android/Android Bootloader Device.
Has worked on every Android device I have owned since it became available.