for XP x64 you need Updates from Windows Server 2003 x64, because XP x64 (NT 5.2) is based on the same Server 2003 architecture. But for Windows XP x64 you can only get the updates until 2015, because Windows Server 2003 was discountined at that year.
Getting XP updates (x64)
Numerous news sources like PCWorld and ZDNet reference this post, but the instructions to get x64 updates are unclear.
I understand that one is supposed to extract the contents of an updater executable into "C:\xpupdate" by executing it in the command line with the "/extract" switch, and browsing to "C:\xpupdate" where it will be extracted.
Then when that is done, one is supposed to run your script "update.cmd".
There is just one glaring problem.
It seems that you are referencing a very specific install/update that isn't specified in your post.