Windows media player trouble

[dynasty]

I was downloading some clips of some different things, and after I watched them I deleted them from my computer. Well when I go back a few minutes later to watch a movie, windows says that it can' find windows media player and gives me the extenstion C:/program files/windows media player. I go in the program files folder and it is there, nothing is missing. What would make this happpen? I'm pretty bored right now, so I might just reformat even though I did it last week, if it can't get fixed. Thanks