Why do hard drives fail?

Question

Hard disks

There is a system. Worked stably as a server for CCTV cameras. 5 disks of 1-2 TB were connected. ASUS board, 775 socket, DDR3, Xeon e5450.

At one point, hard drives began to "fall off".
Constantly appearing in the BIOS, then disappearing. The system from a disk ceased to be loaded.

I checked it with known working other disks, cables, with a different power supply. Same problem. The connectors are also ok. I also thought to check if something would work through the IDE, but there is no socket for it on the board)

If you boot from a USB flash drive (for example, from Linux), then everything works perfectly without any other problems, all performance tests pass perfectly.

What do you think is the problem?

Answer 1

The most likely power supply
And everything else will die from it, change the power supply

Answer 2

The power supply or bus controller aka "south bridge" has problems, perhaps one of the secondary power converters on the motherboard is all. Mother's old, it could have already warped the board from time to time and something came off. If video surveillance is in a critical place, it would be better to change it to something newer / more reliable