If my ex-wife rolled over her entire 401k before I got my 1/2, what do I do now?
You need to consult an attorney in your area immediatley.A QDRO alone does not mean anything -- under Federal law it has to be served on the Plan Adminstrator for the 401k and then accepted or rejected by the Plan Administrator.  Once it is accepted then the Plan Adminstrator divides the account in accordance with the QDRO.  Evidently the QDRO was never served on the Plan Adminstrator in your case.Even though the QDRO was not served on the Plan Administrator most divorce decrees have wording that not only awards you one half of the 401k, but also divest your wife of one have of the 401k.  In most states she will be viewed as a "constructive trustee" holding one half for your benefit.  It will be necessary to sue your ex for your one half.Again, immediatley go hire a local attorney to handle this for you.John K. Grubb