Wireless Internet with Vista Ultimate

Hey guys I have been using Microsoft Vista Home Premium for a little while
now, and running my laptop wireless connected.
Since I have installed Microsoft Vista Ultimate my laptop connection has
been giving me Access to Local internet only.
I am sure the question has been asked thousands of times, but I do not know
where to look and set about sorting this out. As you may know from other
questions I have set in this forum I am a comlete novice when it comes to
computers, so please may I have a step by step guide.

Thanks
--
Bomor