It is an iRiver H120. I accidentally dropped it and now it is asking me to check the HDD connection. I cannot access any files and can't find them via USB on the computer either.
Although I can still fiddle around with various options and listen to the radio.

Is it just a case of opening it up and connecting the Hard drive back, or is it more serious than that?

Ryan Gibson, November 2006

I have a similar problem (same message), not aware of it having been dropped (but it belongs to my wife). I am still able to access the unit via USB tho'. The unit keeps locking up, claiming to have no data and saying 'check hdd' followed by 'check hdd connection.
I've tried formatting the drive and repairing disk errors. I've tried re-loading the firmware and formatting from the mp3 player - but none of those options seem to be working :s
Unfortunately, I'm beginning to think it may be a manufacturer repair job :s

Josh Beckett, May 2009