Well after doing some searching, i came across direct x 10 for windows Xp.
No its not for Microsoft, i believe a 19 year old reverse engineered it, and made it avalible to non-vista users.
you can pick up the files here.
i suggest downloading the patch and the installer, i didn't try using the dll's.
On a side note, The installer is in a different language German i believe, so just follow standard button clicking. (you guys should have gone through enough of installs to guess what they should say.)
I bet its a good idea to have a direct X 10 capable card too.
When you finish, Go to start->Run->DxDiag.
You should see at the bottom direct X 10