Most of those have everything to do with this.
I won't detail which ones have or don't install/use a CODEC but you just gave up a clue there are 3rd party codecs.
Tell me how you configured WMP. That is, did you look in every nook and cranny to tell it not to monitor for new files, move your files, update your files from the internet and more? I can't write tutorials here. Not enough space or time.