Sometimes duplicate songs will appear in your Windows Media Player library if you have the same song in two different locations on your computer. Windows Media Player supports deleting your duplicate files from the player library only, or from the player library and your computer entirely, by using the "Delete" features within WMP.
Turn on your computer and launch Windows Media Player. Click the "Library" tab near the top of the screen to reveal your library contents.
Right-click your duplicate file and select the "Delete" option. For consecutive songs (e.g. songs in an album), click the first title, hold down the "Shift" button on your keyboard, and click the last title to highlight all songs in the list.
Delete non-consecutive songs in your WMP library by holding down the "Ctrl" button while you select the duplicate songs. Right-click your highlighted songs and select the "Delete" option.
Delete items from your computer entirely by highlighting the desired titles. Right-click and select the "Delete From Library and My Computer" option.