I think i need to rephrase my question.
My speaker, logitech z5500, can support both analog & digital input. When i try to switch the input from analog to digital or vice versa, in the same time i have reconfigure my sound setting in the control panel. It used to be okay to use both analog and digital input (not in the same time) without any problem. However, now i can only use the digital input. Whenever i try to use analog the following message will appear:
""An audio device was disconnected or reconfigured. Verify that the audio device is connected, and then try to play the item again."