I have an Acer Aspire 5315, It has the realtek high definition audio. I have hooked up this laptop to a Numark DMX 09 digital mixer and it has worked fine. On the weekend while in Windows media player I got the alert that for a certain file the system had to play it in analog. I cannot find any way to switch it back to digital output and since this has happened I get a lot of noise when I try to hook it up to the mixer. I cannot here any music, just loud hissing and popping and ticking sounds. It sorks fine when a small set of speakers or headphones are plugged in. Can you help me with this problem. I believe that in analog mode the mixer cannot take the signal and I need to put it back to digital, I cannot find anyplace that allows me to do this. In Windows Media Player it says that the output is Digital but in the realtek screen is says analog. I hope that I Have given enough information for you to help me.