Go to Start ---à
type “Devmgmt.msc” . Now you will get a “Device manager Window” . Select the location you want to scan and click on “Scan for Hardware changes” (this is in action menu) . If the issue is resolved it will recognize the device. If this fails open the device manager and now expand the bus control . Go to “USB root hub” in the list and --à
USB root hub properties a dialog box is displayed. Click on “Power Management ” tab. No tick on “Allow the computer to turn off the device to save power ”. Repeat it for 6 of each USB hub.Now go to “Action tab”-à
Scan for hardware changes. Close the device manager. And yet if this method does not resolve the issue then restart the computer and check if you are facing the same issue. And if it is a yes then you will need an expert advice or get an IT support services.