Sansa Express WMA-MP3 Problem

I Recently Deleted All My Music From My Sansa Express 1 GB And My 1 GB Micro SD Card, It Played All Types Of Music Fine, But I Deleted Them because I Needed To Transfer Some Documents , And When I Synchronized New Music Into It, I Noticed That It Played Most Of Them Like If It Was Playing On Some Sort Of Fast Forward, Then I Did Some Research And Noticed That It Only Played MP3 Songs On Fast Forward And It Played WMA Songs Normally, What Should I Do To Play Them All Normally Again