Browser is hanging up on a couple of sites, including MS download for Windows XP SP3?

I just installed qwest with windows live for internet and it included IE7 which I apparently needed, so I installed that from their cd. I've uninstalled netzero and defragged my HD. Everything is working great except when I go to SIRIUS.com, the page hangs up. I'm on Windows XP Service Pak 2, but trying to download SP3 from microsoft it hangs up right when trying to start the download. I've retried several times over 2 different days, but same thing. Any suggestions? Thanks