Help Re Norton!

Not sure if I'm posting this in the right place, but here goes anyway. Since this evening I've only been able to access the internet by disabling the Norton anti-virus. As soon as I enable it, I can no longer get access. Can anyone recommend what I can do to rectify this(apart from getting a decent anti-virus package of course, which I am prepared to do).
Thanks in advance.
By the way, I have no virus protection at the moment, hence being able to post this.