Hello....Please help

All my Audio & Video files show as being Real player files even when some have been downloaded as Windows.
I currently have Windows Media player as my default player.
I have changed the default player to Real player and back to Windows but it makes no difference. Searches now show all files as Real player as aposed so showing both types as it did previously.

Anyone got any ideas as how to sort out the problem?

Many thanks

Twaddy