I use Windows Media Player as the Music Server program. I use loss less .wav file format files ripped to a 300Gb disk on the Toshiba laptop running Vista OS.
In my case, the laptop has a wireless (WiFI) connection to a Linksys wireless router running my wireless network. The Roku Soundbridge connects similarly to the WiFi network and the laptop music server. The digital outputs from the Roku feed my DAC.
So I do not use a physical USB connection, from laptop to DAC, but that should work as well using WMP as the server program, I believe.