Hello,
Can you try a different USB cable, USB port or another computer to see if you have the same problem? Please note, some USB cables are only intended for charging devices and do not have any data lines, so the computer does not recognize the device.
If none of those help, can you post a screen capture of your Windows device manager with the “Ports (COM & LPT)” expanded?
Also, what is the green LED doing?
-Derrill