Windows Media Center vs. Media Player

I have Windows Vista Premium 64bit. I was using Windows Media Player which comes on it. Then I clicked on Windows Media Center one day to check it out, it also came with it. When I went to use my media player to play my music I was informed that it has stopped working, it says a problem has caused it to stop correctly, windows will check for a solution and get back to me. WHAT?! Anyway could the Media Center have turned off the media player? I tried to turn it back on manually but nothing happened.:confused