It sounds like your WMP has been replaced by another player as your computers default player..(does that make sense
)
To make WMP your default player again
Go to your shared folder (outside of Limewire) you will find this folder by clicking on one of your files in your LW library and clicking explore...
Right click on one of your movie files
Select open with
Select choose program
select WMP
and tick the box that says always use this program to open this file type
Select OK