Your PVR is no longer recognising the hard drive. Very often this is due to the internal connections becoming loose. This has been reported to have happened on Humax 9200T / 9150T / 9300T even when the owners have not moved the PVR recently.
THE FOLLOWING WILL INVALIDATE ANY GUARANTEE
Power down the machine and detach from the mains. Using a screw driver take the lid off the box and make sure that the data cable between the hard disk drive and motherboard is firmly seated. Sometimes they look ok but are not and so physically press them firmly in.
Screw the lid back on, plug in and power up.
It is also possible that the hard drive is faulty.
To replace try to obtain a replacement from the same manufacturer and series as the one that came inside the recorder originally.
For the 9200T you may have to settle on using ebay to buy a Seagate DB35.2/DB35.3 series IDE drive where the model number ends in 'ACE' and the capacity is just 160GB.
For the 9150T you could consider a similar model to the one already in your recorder but with a larger capacity. A Western Digital AV-GP WD3200AVVS hard drive has a capacity of 320GB.
If you do replace the hard drive when you first switch the recorder on it will ask if you want to format the drive. Accept the format and it will be completed in a few seconds.
NS, December 2011