Changing Properties in PowerPoint

Windows Media Player Version 9. PowerPoint 2002.
My avi movies (inserted through custom toolbox)will not
retain the full-screen setting beyond one run. I adjust
the properties to play full-screen and it works perfectly
the first time I view the PP slide. Second time it's back
to the small version. When I return to the properties
dialog box, my full-screen option is not checked anymore
and the fullScreen line reads false again. All the other
properties changes I make are retained--only full-screen
reverts back. How can I make the full-screen property
change stick?