Having a content type with a CCK file field, how to set up a view to only show nodes of that content type which do not have a file uploaded?

I have explained my problem here http://screenr.com/6rA

I posted this earlier in text but no one could get the idea about my problem so I made the video. It's开发者_如何学Python only 4 minutes long.

I'd appreciate if anyone can help. It's the last hurdle for me to finish this university project.

EDIT: Someone has done something similar to what I need at drupal. org/node/366665

Am quite a drupal n00b so can't figure out how he has done it.

In the view, create a filter. Filter on "content: (your file field)" is not null.