Try using a different usb port if that dosnt work try connecting your kindle as a camera, if you cant find it on thee drop down list just go to settings and storage on your kindle and select it there and see if your laptop recognizes it. some other things you can do is to use calibre to try connecting the kindle to your laptop, you can install a kindle driver if you dont already have one, or you could uninstall and reinstall usb controllers by going to device manager>universal serial bus>right click the device and hit uninstall device then reinstall it.