Media Player Not Showing File Types.

You know in Windows Media Player that drop down rectangle
box and how if you only want to see .mpg files you can
choose to only show them or if you want only .wma you can
see those or if you want all files you can see that.

Well for some strange reason unknown to me i cant seem to
get anything all i get is an empty bar.

I unistalled media player and reinstalled it and that
didnt work. I even unistalled it and clicked on the setup
file tool in the media player directory and restarted the
computer and that didnt work.