To my knowledge...Windows never has prevented any driver from loading, assuming that the proper hardware is detected.
The warning about unsigned drivers...is routine...and has nothing to do with the ability to install said driver...or the propriety of installing it. I see it routinely and ignore it, as I assume that many others do. To install the driver package, all it takes is an acknowledgement from user that he/she wants to still install it.System Specs
Drivers for the onboard video should be available at the Sony website.