Hi Chas
As James says, it may be just a loose connection.

Regarding HDD in general, it is good practice to replace them when they have reached 2/3rds of the manufactures warrantee period, as this will reduce the chance of unexpected failure.

There are also 3 other things you need to do with any HDD, which are; Backup, Backup and Backup

Hopefully it is just a loose connection
Regards

Bill
_________________________
English Riviera:
Live entertainment, Real Ale, Great Scenery, Great Beaches, why would anyone want to live anywhere else (I�m definitely staying put).