Asio4all with Emmlabs DAC2

In most cases if the card's driver supports Vista it will support Win 7.
Here's another ASIO driver you can try, though it's not free it works well USB-AUDIO

What type of OS are you using for your Music server? Move to
Windows 7, buy a hi grade audio card with SPDIF output
supporting at least 24/192 or better output. Use a Media
player that supports WASAPI. This way you'll know you're
getting bit perfect playback.