Installing LP 16 Drivers

Hello.
I’ve done everything strep by strep few times and my pc doesn’t recognise lp16 still.

During installation, when the message appear I’m connecting device (USB at the front panel is empty). Installer recognise the device and keep running installing process, but at the same time my Windows 7 64bit show notice on the left, bottom corner of the screen that Windows couldn’t install the lp 16 driver. But installer is running still. Then Windows show massage at the middle of the screen that system doesn’t recognise some certificate but is asking do I wanna install the driver anyway. After choosing “Yes” the installer finishing all process successfully. Then my system show last message: “This version of Windows requires all drivers to have a valid digital signature”. After that I can open small icon with mixer but it doesn’t see lp16. Firmware update tool doesn’t recognize any device as well.