Third. Do a ping test. ping www.bbc.co.uk
use the following command in command prompt.
ping www.bbc.co.uk /t
that is a continues ping and wont stop until you close the window.
keep an eye on the speed. see if it jumps up while playing or browsing web site. a small jump is fine but a large jump and staying up there is not.
I was having network issues a while back and created a simple program to ping a website regularly and plot the resulting time to a graph. It works nicely for isolating when the problems are occurring. For example I found out it was only occurring when my housemate had his netbook on, a polite question later and we found out he had 300+ torrents seeding that he didn't think were causing a problem because he'd already downloaded them

I can put it up somewhere if people want it, it's a tiny exe.