Mp3 files locked as vlc

Hey, I'm not amazingly flash with my mac, but I have a basic understanding, normally enough to get me around, but I'm completely confused with this..
Recently I was given a cd full of songs that I wanted to put into itunes, and while some were already formatted to open into itunes, some seem to be unable to be put on?
The icon is different on these files than with the ones I can put on itunes, the icon being vlc for some reason, but these are definitely .mp3 not .vlc. I have tried going "more info" and changing "open with" to itunes but it says i do not have permission to do so.. Is this because they were bought from the app store and thus will not work on a different computer?
Any help would be appreciated
Thanks in adavance

Firstly MaxW, its not a good idea to publicly announce you are trying to share music, especially from the iTunes Store. You don't want the Feds banging on your door.

Ok, On the modern Mac the Icon and Application comes from the file extension, it has nothing to do with the file contents. This is controlled by Finder. The fact that you can't change this is a worry. To fix this try a Restart. When you change this in Get Info it does not change the file, just Finders list.

If the File has iTunes protection then its Icon may have a small lock on it. The easiest way to tell is in iTunes show the Kind column and it will have ACC Protected.