Extract the files.
Run \"setup_wm.exe /Q /R:N\"
It is also possible to run it like this without the first manual extraction:
wmsetup.exe /Q:A /R:N /C:\"setup_wm.exe /Q /R:N\"
But hence that this wont \'really\' give the user the real quiet and unattended installation they want, as the first time you run WMP 9.0 after that the user must configure it some meaningless settings for WMP.