My Windows 8.1 computer will not scan my Nikon D90 camera. When I plug the camera in and turn it on a full screen pops up that says "D90 - scanning USB device" and hangs. When I manually exit that screen and open Windows Explorer it's blank, i.e. no folders or any drives, it starts a refresh and never quits and the window stays blank. If I then turn the camera off everything appears in WE instantly as expected. Same thing in Lightroom....when I try to import images from the camera the program freezes in a couple of seconds and has to be manually closed and reopened. This camera/computer combo used to function perfectly, but I don't know if that was with Win 8 or 8.1, as the computer may have been upgraded since I last did any photography. Is it a driver issue, software, what? Hope someone has some ideas. Thanks.