Sony RDR-HX900 Help please!!!!!!!

I am pretty new at this, so please bear with me. I have a Sony
RDR-HX900 that is flashing HDD Error. I have tried doing what the
owners manual says to try at fix the problem, but so far no luck.
We have tried changing the drive to another one, but that does not work
either. Does anyone out there have any other suggestions??