Another Local only problem

Hello,
Wondered if anyone could help me. My computer is an Advent and is running Vista 32 bit I have played with her a little in the last upgrading the RAM and it works great.
Recently it has got very very slow taking up to an hour to boot so I stripped it down to find the inside choc a block with fluff. Using a small soft brush And hoover I cleaned her and the worst area was the power unit. Starting her up she booted in just over two minutes which is amazing and works through Word etc fantastic.
However I have spent half a day trying to get her to connect to the router/internet and it just shows "identifying" when trying to connect. I have uninstalled the network adaptor and reinstalled put in the auto connects as I have googled but no good. I noticed then that she was calling it a public network! And not sure if it should be private? I cannot find a way of changing it as with it "identifying" all of the time I never get to see the customise icon to change it?
I have it connected to the router via an ethernet cable which I have checked out and wondered whether one of these usb to router dongles might be my answer?

Any help would be appreciated... Happy New Year, Colin.

 

um, um, um. My memory is that Vista ASSUMES you're connecting to a public network when you install a router, network card, or whatever, and you have to inform it otherwise if you want a private system. Click on the "Open Network and Sharing Center" panel, click on on "Change Your Networking Settings" and so on.

Let us know what happens next.