Does anyone use the Tascam US-600

i've had nothing but headaches with mine, wow  I've tried everything, I've got it where it works fair during playback. But as soon as I stop playback, I get a "drop out" message, and the engine stops. It seems like I have to unpower then reup sometimes to get it back on track. It has a wall wort for power.  Sometimes the drop out happens during playback.  Since upgrading to Win 7 64 bit I had to deep six my m-audio delta-66 and went for the Tascam US-600.  I don't know if it's using a USB interface or is it just the Tascam US-600.  I've always had very good performance and luck with Tascam, maybe they've been purchased or restructured or what ever, I don't know, but this is really starting to piss me off............
 
Thanks for any help,
Dan