My first experience with Vista - can't access web with IE7

Hello (this is great, I just discovered the msnews server!).

My new laptop finally arrived from Dell with Vista installed. This is my
first exposure to Vista. The machine is installed with Vista Business. I use
a home wired-only network, with two other PCs (running XP Home) and a
networked printer attached. My workgroup is named "HOME". I have two
problems that I don't know how to solve. All machines are "pingable" from
one other, and the XP Home machines have the latest updates applied.

- I can't access the internet using the pre-installed IE7. I managed to copy
across and install Firefox, and this works fine. Any ideas why this could
be?

- Also, when I select "Network and Sharing Center", only the new laptop is
shown connected to "Internet" through "Network". I supose that "Network"
corresponds to my workgroup "HOME". When I click on "View full map", one of
the other PCs is shown connected to the LAN (shared maps on this PC are
accessible). The other PC (its shared maps are not accessible) and the
printer (its shared maps are accessible) are listed under the heading "The
following discovered device(s) can not be placed in the map". What does this
mean?

Can anyone help me?

Many thanks,
Paul