USB DACs and devices not found : windows

Establish on a different computer that the device is ok

http://support.microsoft.com/mats/Windows_USB_diagnostics

Problem found on:SMSL Sanskrit (not 6th anniversary) after using prior USB DACsThis had a SA9027 . Also not always happy with HTC One M7 - OTG

Environment variables
devmgr_show_nonpresent_devices = 1

Also 
Click View tab and select Show hidden devices