Windows 8 has a security feature which will not allow you to install Unsigned Drivers or the drivers without digital signature.
If you are having trouble on your Windows PC because of this feature then you can simply Disable Driver Check Enforcement on your Computer.
First, press "win + I" to launch the charm bar, and click "Change PC Settings" at the bottom.
Then, go to "General", and scroll to the bottom of the page, click "Restart Now" button under "Advanced Startup" section.
The computer reboots to a "Startup Menu", then click "Troubleshoot"
Click "Advanced Options" at next screen
Click "Startup Settings" at next screen
Click "Restart button" at
When your computer reboots another menu will appear.
Item# 7) is to "Disable driver signature enforcement".
Press number 7 or F7 to continue booting to Windows 8 with digital signature enforcement disabled.
when you install the driver you will get the following prompt,
this driver software anyway"