It looks like your PnP(Plug and Play) does not seems to work properly and you can try out the following steps

1. Insert the USB
2. Right Click My Computer and click on Properties
3. Go to HardWare tab
4. Click on Device Manager Button
5. Right Click on the Tree View and clcik "Scan for Hardware Changes"

This should probably detect the new hardware inserted correctly.

Thanks
Shabbir.