Hi De Rossi,
Please make sure you have installed the KB3123479 hotfix.
[Windows requires a new extended validation code signing(based on SHA-256) mechanism for drivers. Earlier versions of Windows 7 and Windows 8 cannot verify the new certificate, in which case please update your windows with the hotfix KB3123479.]
If you have previously installed the LP-16 please uninstall the driver.
Reboot your PC
Make sure you have no USB drive connected to the LP-16
Start the driver installation and connect the LP-16 to the PC when the driver ask you for this.