My computer is connected via usb to an idsd micro dac. Recently the computer stopped working and was beeping on startup, which I fixed by removing and reseating the ram cards. Now the usb audio is not working - the dac is working when I connect to it via coax from my cd player, the audio from the hdmi output of the computer is working when connected to my tv, and the audio test signals are working through my stereo system, so this issue is obviously usb related. Any help would be greatly appreciated. Thank you.