Win8 enforces driver signatures by default. If you have a Win7 driver that worked OK, I suggest the following to disable driver signature enforcement:
From the Metro or Desktop
Bring up Charms by mouseing over to the right of the screen
Go to Settings
More PC Settings
General
Advanced Startup > Restart Now
Trouble shoot
Advanced options
Windows startup options
Restart
Click on 'Disable driver signature enforcement
Reboot
Install the relevant driver, allowing the non signed driver to install.