We have a DA305 that worked just fine for about 4 months and is now dead as a doornail.  Testing on 3 different machines a none of them see anything when we connect it, and all of the ports are non-responsive.  Every time I try to put in a warranty claim, I get asked for the service tag.  I've tried every number on it I can find and nothing works.  Is there a service tag and I'm just blind?