Does anyone know a quick and easy way to resurect dead tracks?

[GOS]

:( Recently I converted all my itunes tracks to MP4 using Ovolab AAChoo 1.1. This was initially fine, however occasionally it would crash or hang whilst converting. And then I started to notice that dead tracks were starting to creep into my playlists. I used to go through the process of helping itunes locate the missing track. Then I started to notice that there were heaps of dead (!) tracks. When you have a large amount of mp4s its time consuming (even doing one track takes a while). Does anybody know a way of resurecting the dead tracks in itunes? I'd like to be able to do it quickly and painlessly.

Thanks in advance.