does my printer blocks the networking?

hi. i have a question about the network.
i just upgrated xp to vista. till then, i have never had like this problem.
but now, right after i open windows, the internet doesnt work.
in the network panel, there are always two connections, which are private
and public. my computer is a desktop with no wireless lan port.
i had dsl which is set up as private.
so then whats the public??
in order to use the internet, i have to disconnect both and connect only
private connection then it always works.
but i want the internet to be connected right away when i open the computer.
additionaly, my printer is not wireless or for sharing. but seems like my
printer blocks the connection because a printer icon always appears in the
network panel.

so i would like to know how to set my private connection as a dafult and
delete or disconnect or disable the public connection which will be
automaticaly set as starting windows.

please help meee!! grrrr....