OS Win7 Ultimate
Acer Aspire m3910 64 bit with built-in sound card (NO stereo Mix)

Is this possible? I have tried every way possible to enable Stereo Mix, It just doesn't seem possible on this computer. If I could get a command line example for sox to do this I would sure be thankful! If Sox is unable to do this, would one of those Usb plugin sound boes bypass my soundcard and provide stereo mix?
Thanks,
Paul