If you're not able to install your monitor drivers with the driver pack "Standard Monitor Driver Signed Windows 10 x64 " downloaded from ViewSonic website, please follow below instruction to manually install Win10 x64 driver.
1. Download the attached ZIP file including monitor drivers to your PC and extract it.
2. Under "Control Panel", open "Device Manager".
3. Find the Monitor which you want to install/update the driver under "Device Manager" and double click the icon.
4. Go to the "Driver" tag and click the "Update Driver" button.
5. Choose the second option to manually locate driver software.