Hi and welcome
First, Itunes 9.0.1 is giving us all grief. I have worked at least 6 broken installs.
If yu want to find exactly whats happening. go into event viewer (type event viewer in search), windows log, application tab. Look for app crash, app hang, that mention Itunes. You want to only look for errors (red "X" in left column) they will be there. let us know what they say and what the event ID is and the source code is.
thanks in advance