Windows Vista 'N' & Windows 7 'N' editions are sold in Europe without multimedia components
for legal reasons. This prevents MP3 playback, along with WMA playback and tagging (in both cases
the files will become grey on attempts to play them).
In order to resolve this:
1) If you don't use WMA, the simplest approach is to install an MP3 codec as described here:
http://www.mediamonkey.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=101
2) If you require the use of WMA, then install Windows Media components as described here:
http://www.mediamonkey.com/support/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=92