My computer, win7 64 bit.
I recently installed a driver without a digital signature, and the result keeps showing an exclamation mark! No, it prompts no digital signature. This is why win7 forces all drivers to have digital signatures for security considerations. So don't blame others.
So I searched a lot of tutorials on the Internet, and there are two recommended for children who have similar problems:
The first type: f8 before booting into the system => enter advanced options => prohibit driver signature enforcement. ok, at this time the exclamation mark disappeared. However, this method is more troublesome, and the previous operation must be cycled each time the device is turned on.
The second type: win+R shortcut key to enter, enter bcdedit.exe -set loadoptions DDISABLE_INTGGRITY_CHECKS in the command window, and then restart it.