Hi Edward,
The driver hasn't been digitally signed by a verified publisher. The driver might have been changed to include malware that could harm your PC or steal info. In rare cases, legitimate publishers do change drivers after they've been digitally signed, but you should only install an unsigned driver if you got it from a device manufacturer's disc. Installing unsigned drivers are at your own risk.
I would suggest you to boot the computer to advanced Windows startup options and select Disable driver signature enforcement mode which allows drivers containing improper signatures to be installed.
Once the drivers are installed, you can restart the computer to normal mode.
Hope it helps. If you have any further issues on the computer, please post your question regarding Windows and we will be happy to help you.