Cannot access Windows update page

[ccursons]

I have had a new modem installed after the last one failed, but just before that I had installed XP sp2, since getting re-started with the new modem my desktop pc can access all internet pages fine, but my laptop which connects to the internet through my desktop via a cat 5 crossover cable cannot access the windows update site.
Has anyone had a similar problem and can help, Im getting really frustrated, Ive tried un-installing sp2 from both machines but this has not resolved the problem, before my BB modem was changed everything was hunky dory.

[Scrubbs]

control panel/network connections might give you an idea...is your laptop talking to your desktop?

[ccursons]

control panel/network connections might give you an idea...is your laptop talking to your desktop?
yes it works for transferring and sharing files and for everyother site Ive tried apart from Windows update and NTL service status. Its really bugging me, if I connect the BB modem directly to the laptop everything is fine, and the desktop works fine, but if Itry to connect to the update site through the network I just get a blank white page...