You could try this
Netgear's recommended setup involves installing the WPN311 driver, then disabling Windows' Wireless Zero Configuration and replacing it with the Netgear Smart Wizard (all this is done for you by the installation program if you select the recommended option).
So after installing the WPN311 in my PC running Windows XP Pro SP2, I suffered from frequent 'blue screen' crashes, with the technical info on the blue screen confirming that the WPN311 driver was the source of the problem. I called Netgear technical support, who recommended uninstalling the drivers, then removing the PCI card and installing it in another slot, and then reinstalling the drivers. All this was to no avail - the problem persisted.
The solution - which wasn't given to me by the Netgear techies, but which I found on an internet forum - was to disable the Netgear Smart Wizard and enable Windows' Wireless Zero Configuration again. This didn't remove the problem entirely - I still get 'blue screen' crashes sometimes when using VPN - but crashes are now quite infrequent.
Netgear has released a new driver for the WPN311 (the installation process of which requires the physical uninstallation and reinstallation of the PCI card!), but it still doesn't fix the problem - "Some configurations using Windows XP Professional, SP2, cause computer to freeze with a blue screen" is still listed as a 'known issue'. Word on the internet forums is that the problem is unlikely to ever get fixed as Netgear doesn't have the necessary programming resources assigned to the task.