open up Windows task manager and check the PlugAndPlay service and make sure it's running. Next, go to Device Manager and check each USB hub and ensure they are working properly. If they are then update the driver for each port. This should tell you whether it is a hardware or software issue. If the ports report problems then it's probably a hardware issue. If both the above are normal then run an antivirus program. It could be a nasty malware or even a rootkit.