Hi sazzle20
Welcome to the eForum
The answer to your question will only become evident if you do the following.
Shut down the Vodafone software and remove the usb modem.
Reboot and BEFORE you plug in the dongle...disconnect Norton.
Plug the usb in and load up your broswer and do a simple google search etc.
If all ok so far, then turn Norton on and if the world goes haywire then you know the answer...Norton.
So as I can check your area , just to be on the safe side, please post your postcode and model of usb you have.
Many thanks
Albert
eForum team