Is it possible to restore my Sony DVD recorder to proper operation ?

Whilst making a recording on my Sony DVD Recorder (RDR-HXD 860) and watching another programme the notice HARD DRIVE DIRTY appeared on the TV screen. I switched off the recorder at the mains and on seeking to start it again the notice HDD ERROR appeared on the recorder. I followed the instructions in the manual to try to cure trhe problem, but after the WELCOME sign, HDD ERROR always returned however long I pressed the start button. I should mention that the hard disc was recording close to full capacity when the fault occurred.