My zune is adding tracks that are already there...

I have a Halo 3 edition Zune 30GB and for some reason I only have like 2.80 GB left in it. When I search how many songs are on the thing, it says like 4575 while in my computer and especially in the zune collection tab it only registers 4072. Any ideas?? Because I'm about to format the thing, it's got me THAT annoyed!
Thanks and peace out!

Microsoft Product v1 has bugs and glitches?!?!?! Oh n0es!!!1