Be Right Back, Uninstalling

so i recently switched to windows 7, and when i transferred my backed up music collection back to my hard drive, a lot of the tags were missing.  ok so no sweat, got those all fixed.  i decided to use windows media player this time around, since i can stream stuff to my xbox.  however some of the songs are missing track length.  i have no idea how to get the track length.  until i can get track length, wmp does not let me use seek in my songs.  only fast forward.  any help guys?

graped

I've seen this problem before. I think my solution was to re-import the albums that were affected.