how do I install a usb device driver for unrecognized usb devices  

Hi, One of my usb to ethernet, usb device is not being recognized, which is essential for network purpose.
I know the drivers can be downloaded for this device.
But if i try to click inf file to install, it prompts alert that this driver is not supported for this mode.
If the device is shown in device manager, after enablilng hidden devices, then how i could install the device drivers so that , i could get the red llght in the usb to ethernet adapter to show that it is running correctly.
Is there a way.