The PSU is one of the things I actually replaced fairly recently (two years). When another HP o f the same model went dead before, I suspected the power supply, and bought a few more on Amazon that had been "re-newed". But it turned out to be the motherboard, which is why I am suspecting it this...
I have a drive, a 3TB Seagate Constellation Drive, Sata, inside of a single-dive Mediasonic enclosure that I used as a backup drive for my media files. Normally, I use SyncBack for scheduled backups, but I turned it off sometime last week. It copies media files from my C-Drive then deletes them...