From the desktop go to the start menu and select computer, then at the top of the window select system properties. When in system properties on the left side at the top select Device manager.
With Device manager open you can scroll to the bottom item where is says Universal Serial Bus Controllers and If you see the whole list of devices and controllers already displayed then that means there is a problem because all you should see normally is Universal Serial Bus Controllers as a one line description. At this point what your looking for is a small yellow circle with a question mark or exclamation mark inside the yellow circle. This will tell you which controller or device is having a problem. You can then delete it and reload the drivers to see if that will fix it.
If there are no yellow circles with anything inside then by clicking the + on the left side you will get the drop down like what is displayed in the screen shot above.
You will notice that there are quite a few items being displayed after that + was selected and depending on how many USB ports that you have in total and how many devices and hubs the list can be quite long. As long as there are no markings and by randomly selecting a few items you can check and see if they are functioning properly.
If all the USB ports are not working and you go to device manager you will need to see if any controllers , devices and hubs are listed. If there are none then what you need to do is take the installation disc that came with your motherboard and install the USB drivers. If there is no disc then you can go to the manufacturers support web page and download the drivers from the site to install.
Another thing that you can check if the drivers are loaded and still no luck is to go into the bios and under the Advanced tab make sure that the USB controllers say enabled.
If your unsure of the bios settings you can always set it to factory default or optimized and make sure that if you have a SSD that the sata controller is still set to AHCI if you had previously set it there.