Im in the same position, i have NPF as well, and i turned it off and it still won't connect. Exept, mine says some crap about a default gateway when the connection troubleshooter is run. It says it is offline.. my default gateway is nothing on my network card, and has never been anything, ever, since i connect directly through a usb adsl modem.
This problem happened as soon as i installed the latest 311 update.
I have no idea how to fix this, stupid microsoft and your badly built programs