Greetings,
Welcome to the forum.
I am not a HP employee.
It sounds like you may have a motherboard problem (SATA controller) if a new HDD and new SATA data connectors don't help.
Do you think the PC was zapped during the storm?
Run HP Diagnostics to check all hardware.
Tap "ESC" at boot.
Select "F2".
Run fast and extensive system tests. Run component tests.
Regards