usb ports are not working. one usb port on left never worked properly...only will work with certain things like my keyboard, fitbit, etc., but not with my external back up system. My right usb ports currently work for my wireless mouse and iphone, and worked until recently for other devices, but recently stopped working for my external back up as well as my tablet, camera, etc. file manager / device manager does not show/recognize anything plugged into these usb ports. However, just today, when i plugged in my external back up it made that "sound" but still no recognition elsewhere. Please help. Have not tried to download new drivers yet. Have tried some simple steps i found online, but they have not worked. Thank you.