How do I retrieve missing data from tracks

Hey Pioneer!

I downloaded the new rekordbox software.  And I'v managed to retrieve the missing data from only some of the songs on my USB device which are in my collection.  The other music which can't "retrieve the missing data", are not in my Collection database as the last computer I had broke.  My question is,  Is there not any way to retrieve missing data from the tracks which are not in my current collection? Or do I have to delete those songs, and import them again onto the USB device?

It would be great if the songs could be re analyzed on the USB, WITHOUT having to refer to the collection on the computer.

Thanks alot.

Oliver