I know, this is a problem, mentioned earlier.
Intalled XPpro SP3 with empty files: win51ip.SP3 and win51ip.SP2
Sardu saw it thought SP2.
I made a new intall with added file win51ip.SP1 testing, if that´s the reason.
Now Sardu saw it SP1.
So i understood, that it would only have file win51ip.SP3.
New install and all fine. Sardu sees it right as SP3.