Already visited the official troubleshooting site, and really the only solution which is kind of relevant is to do with problems caused by having a firewall running (which I've already taken into account). So, reinstalled both XPSP1a and IE6SP1, and the Automatic Updates service seems to work now, but I still can't access windowsupdate.com for some reason (still no error message) And now, even though IE works fine, every time I log on to Windows I get a dialog asking me to update IE6 - if I accept this it'll tell me a newer version is installed, and bomb out. Great - but it'll do this process every time I start Windows! Anyway, cheers for your help chaps.