Speaking of KMPlayer, I have just encountered another problem. I think that was due to my registry repair software. I could open neither my audio files nor videos and I could not find KMPlayer on my program list.
KMPlayer can’t be found in either “Open with…” or “Default Programs” menus.
Download this file
Rename it to VistaDefaultPrograms.reg (just remove the .txt extension) (Just in case you can’t find the “.txt”please have a look here)
Double click on it and accept the registry modification