Sad thing is I have a legal copy of XP for just about every computer I have had, and I choose not to use them because of one bad experience with product activation(yes I did call, and did get the Inspiron 8100 reactivated + Office XP reactivated), o and dell doesnt provide you with real CDs, only a partition with the bloatware that you want rid of for all new systems.
You do not need any .dll replacement file, nor bypass script. You also can leave autoupdates running as far as I know as well.
If you want, find the downloads on downloads.microsoft.com, and search for the file names on google, there should be a mirror. Most updates do not require Genuine Advantage anyways, its really just anything they consider to be a new feature. Believe me WM10 is very easy to obtain, and I also have a legal machine or two to do it if I want directly from their site. Finally if you do use mozilla go to
http://windowsupdate.62nds.com/
Do not expect microsoft to support your actions or make it easier to pirate, that is just stupid. You must keep up with updates on your own since you are not using their product how they intended.
BTW it is funny how the windows auto updater still trys to install TAPI, MSIE, Outlook Express, and other software updates even after you have stripped them out of the OS. Nlite is a great product and another reason I do not use Microsoft's legal methods.