get a usb 2 device and plug it in and see if it works .
When I plug same usb device to the top port it does not work, but if I plugged to the bottom port it works.
I have not got same problem before, this happend recently.
The device that I plugged to the both port is same.
Now may be top port is USB 1, and down port is USB 2,,,,,How can I find that ?