It sounds like the "Click of Death" which is the drive heads misaligned on the HDD platter. Did you have any warnings? This could be caused by an impact and if by any chance it does start up you must back up immediately without disturbing it again.
Recovery of the files and data is possible but requires a specialist company who can dismantle the drive to do so. Quite expensive the last time I googled it. I`m sure someone may be able to make a personal recommendation for this service.