Driver signing can no longer be disabled on Vista. Everything is hard coded to
There is no more Ignore or Block policy available in the product code.
We cannot suppress this "Warning" dialog box. The only way for us to avoid it
would be to sign the driver package.
On x86 unsigned drivers will load, but you will always see the warning. However,
once the driver loads, it becomes
part of the driver storage so, uninstalling and reinstalling the unsigned driver
should not produce the Warning dialog again.
Please use Makecert that’s included with the WDK to sign the driver: