When trying to access iTunes Store from iTunes installed on Windows 8.1 it crashes. Problem is that iTunes can’t find specific DLL which is used to display content of the store.
In order to fix problem cop: QTMovieWin.dll
from: C:\Program Files (x86)\Common Files\Apple\Apple Application Support
to: C:\Program Files (x86)\iTunes
and now you can access iTunes Store without any problems on Windows 8.1.