Here are the latest drivers and management program for that specific device - http://support.netgear.com/product/WNA3100
(Just click on Software Version 2.1 (Supports Win8) )
You may need to uninstall the original drivers entirely which you can use " Start > Programs > NETGEAR WNA3100 adapter > Uninstall NETGEAR WNA3100 adapter " OR use Windows Device Manager to remove.
It should be noted the official instructions say to remove the device before installing, so this is the first step I would take.
(Edited because specific Windows 8 drivers were found, rather than just the AIO)