If you are struggling with getting your drone to connect to your computer for Betalfight/BLHeli, make sure that you are using a data USB cable. Some cables are only for power/charging, and do not have data lines. So, try different USB cables first.
Next, if you are still having issues, keep your drone plugged in via USB, and try running this Driver Fixer:
As a last resort, you can try using the Boot button on your drone's flight controller board (not the Bind button). Using a non-metallic tool, press and hold the Boot button while plugging in the USB cable and powering up the flight controller. That usually gets you into bootloader/DFU mode. Do not worry if your flight controller's LED's do not light up. You should be able to flash or reflash the original firmware at this point using Betaflight Configurator.
Connecting to Betaflight