Audio driver?

Ever since a couple of days ago, I've been having driver problems. I have a realtek AC'97 that came with my motherboard and it has never failed me until now. Basically what happened was I tried to play an audio file and the message came up that the audio device could not be found, so I uninstalled the whole driver then re-installed it. At first Windows Media player played a song, but Now, I can hear all the normal windows sounds but i still get the same error message from the media player. Plus, it says I have no audio hardware plugged in but my drivers are all working properly. Any ideas?