So why this problem just started, I don't know. Windows 8 64 pro with a Xonar DX sound card. Works fine on start up or restart, but wont work after waking from sleep mode. Devise management says it's working fine but ITunes or Pandora, (or anything for that matter) won't play. Checking compatibility, says Xonar DX isn't compatible. Why now? Anyone else have this problem. As a temporary fix, I just leave the computer on most of the time and never let it sleep.