Hey there, mickey716.
That's a bit strange. Does it show up in Device Manager? Is there any indication that the drive is powered up? Have you had any issues with other storage devices when connected to that computer?
I'd recommend that you backup your data, just to be on the safe side and test the drive with an HDD diagnostic tool to see if anything alarming pops-up. If everything seems to be fine with it, then I'd recommend that you uninstall the drive from Device Manager (if it's recognized there) and reconnect it to the computer, so that Windows can install its drivers again and see if this fixes the problem. I'd also suggest that you try all the ports on the computer to see if you get the same result, you could do that with a different USB cable (not longer than 12").
Hope that helps. Please let me know how everything goes.
Boogieman_WD