Ok now i looked at the device driver download that warlordfmike advised off so i decided to post a link to the
C-Media CM6501 Like USB Audio Driver instead to see if this would rectify it firstly
Also here are some preinstalled audio bundles
http://dlsvr03.asus.com/pub/ASUS/Audio_Card/Drivers/Xonar_U1_V61282012LO06_Vista.zip
http://dlsvr03.asus.com/pub/ASUS/Audio_Card/Drivers/Xonar_U1_V61282012_Vista_LO04.zip
Now it also looks like its not set for playback
1. Start\Control Panel and in the search area type sound
2. Select Manage Audio Devices
3. On you screen it should tell you what playback device you are using and it should tell you if its working.
4. ok now select the device you want to use
5. Select properties
6. At the bottom there is a drop down menu called
Device Useage
7. Select
Enable and select apply and ok
Regards
Craig