Windows 7: Songs in WMP are not listing alphabetically, Sorted by Artist

I recently added a new artist (folder in my Music directory) to WMP and the songs aren't sorted alphabetically. I have the songs sorted by Artist and the majority of which are sorted alphabetically under each artists name. But songs under certain artists aren't sorted alphabetically. Does this have to do with the ID3 tags or something else?

I've searched the internet for solutions and can't find anything. I searched this forum as well, to no avail. Sorry if this has been answered elsewhere.

Thanks in advance.