Couple of thoughts:
1: Are you using the online installer or did you download the full "network professionals" offline installer? When it comes to service packs, I tend to recommend people skip the online installers completely. One little hiccup in your Internet connection and all hell can break loose with your system. If you have the full offline installer, did you consider the possibility that maybe you got a bad download, and that's what is causing your problem?
2: Did you check to see if Dell possibly has a special version of Vista SP1 for its systems? While not common for Dell, sometimes OEMs have to make custom versions of service packs as a result of changes they make to the operating system to tailor it to their systems.
I've been trying to install Vista SP1 without success, all I get is the error message 800B0100.There seems to be no solution for this problem but re-installing Vista! My PC is a Dell Dimension E521 and works fine. All the other updates are installed without a problem.
Maybe someone has a solution and/or advice in this matter. Thank you in advance.
Regards, dushi 37