I have lots of songs which are Windows Media Player files. All of these files were working fine. After I formatted my laptop, most of them stopped working with Windows Media Player. Previously I was using Windows 7 Ultimate 64-bit, and I installed the same version when I re-installed, but still the files are not working. When I try to play those files some message is showing like files are compressed are not supported or something like that. However, the player is working fine if I play movies or few old files that are working. Wht might have gone wrong?