When I resume my system from sleep mode the audio does not work. There is no audio device located in Device Manager. I had faced this issue a number of time. The system that I am using has Gigabyte 965P-DS3 motherboard. The audio codec which is used in it is Realtek ALC888 HD codec chip. It is a new system and I had just recently installed Windows Vista on the same. The drivers that I am using on it is from the official website. The sound device is just disappeared. To find out whether there is some hardware problem I installed XP on a second partition. It is working quiet fine on that.