I have a zinwell zmt 640 pvr.
It shows it has a full hdd but there is nothing on  it in the channel list. When I try format it in the zinwell it the progress bar stops after about 10 seconds then I can't do anything apart from turn it off at the wall. 
I pulled the hdd out and stuck it in my pc installed windows on it seemed to run fine, checked the disk for errors etc. I put it back in the zinwell, but same thing it shows as full and won't format