By default, Windows 8 disables the installation of un-signed device drivers.

To overcome this, you can override this behaviour by changing the "Advanced Startup options" (Under Win8 -> Settings).  

Before you proceed the configuration, it's advisable to Close any open apps or documents first, as you will be shutting the PC down)

Steps starts here:
1) On Windows 8 Desktop, Move mouse up into the Top/Bottom Right corner and select "Search".

2) Select "Settings" and enter 'Advance Startup options' in the search textbox. 

3) Select "Advance Startup options" shown on the left. 

4) You'll come to 'PC Settings' page, on the left panel, select 'General'

5) Scroll down to sub-section "Advance start-up", pick "Restart now".  

6) Now, pick "Troubleshoot" -> Select "Advance options" -> Select "Start-up Settings" -> Select "Restart" button

7) On "Start-up Settings" page, press F7 (Disabled drivers signature enforcement) 

Congrats! you will now be warned about installing unsigned drivers as you were in previous Windows versions instead of a complete failure to install.