Some of the files that you're seeing could well be fakes. Read through those 2 links in my last post for more info

If a file's downloading, then suddenly stops...the person you're downloading from might have gone offline. In that case, you can right click on the search result for that file > search more > get more results. Or, start a new search...that can sometimes start a download up again.

Remember that what shows up in your search results depends who's online & what they're sharing at the time. If you're looking for rare files, it could be that nobody's sharing that file at the time of your search...so you won't find a result for that file.
You could try connecting to different ultrapeers, that can give you different search results. Click on the Connections tab. You'll see a list of ultrapeers that you're connected to. Right click on an ultrapeer > remove. Now a new ultrapeer will take the place of the one you've removed