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
Advanced Startup > Restart Now
Windows startup options
Click on 'Disable driver signature enforcement
Install the relevant driver, allowing the non signed driver to install.
This has worked OK for me installing various old printer drivers. Just make sure you know the provenance of the driver being installed, as always.