Run: gpedit.msc
Open the Group Policy Editor and expand the following branch...
User Configuration | Administrative Templates | System | Driver Installation
Double click "Code signing for device drivers", and under the "Setting" tab select the "Enabled" radio button. In the "When Windows detects a driver file without a digital signature" dropdown, select "Ignore". "Ignore" directs the system to proceed with the installation even if it includes unsigned files.