Audio device on high definition audiobus prob

Hello, could somebody help me fixing my pc's audio problem?when i tried to play my windows media player this will pop up "Windows Media Player cannot play the file because there is a problem with your sound device. There may not be a sound device installed on your computer, it may be in use by another program, or it may not be functioning properly"..
and when i looked at the device manager the "audio device on high definition audio bus" is in yellow spot with exclamation point...and the device status was "The drivers for this device are not installed. (Code 28)
To reinstall the drivers for this device, click Reinstall Driver."
what should i do?
my system properties was Microsoft Windows XP,Professional Version 2002, Service Pack 3,
pls help me in my problem..