Glad you got the movie playing. The upside down problem has different causes and solutions, you could try:
1. To just watch it in WMP and be happy.
2. Uninstall all codecs and install the ones you need again.
3. Use
ffdshow instead of DivX/XviD (uninstall DivX/XviD first).
If ffdshow doesn't solve the problem immediately, you can check the "flip video" (or something to that effect) option in the ffdshow configuration window.