My computer became muted...

Hello,yesterday when I viewing a site from china(i forgot it address),my theme suddenly change from xp theme to classic theme,but it change back xp them after i close the site,but today when i open my computer,my computer became muted...when i want to play a song,it write:
Windows Media Player cannot play the file because there is a problem with your sound device. There might not be a sound device installed on your computer, it might be in use by another program, or it might not be functioning properly.
when i go to the sound and audio device properties,at volume,sound playback,sound recording... all it show no audio device,but at hardware ther it show the device is working properly,is this the conficker virus??