CODECS

hello, can anyone plz help me iv downloaded and instaled this codec and when i installed it a black box came up and went but then when i wanted to dlete the installer it says its in use. iv restart my computer and removed it from the add/remove programs but ti still just stays there and i cant delete it.please can you help any one. oh and by the way the codec is for windows media player and its called hdx4 thks in advance.