The hard disk of Western Digital is broken, and someone has repaired it. The other party said that it was dismantled, so it was not sent back to the factory. What should I do? Can it be repaired?

As long as it is dismantled, it can't be returned to the factory, but the hard disk damage can generally be repaired, provided that there is no major physical damage (small bumps are not a big problem, as long as you don't fall). Find a computer hospital, check the disk and repair the bad track. If there are several physical bad tracks, they can still be used after shielding. Generally speaking, the problem can be solved, but one thing is that the service life of the hard disk will be shortened a lot after maintenance, so it needs to be repaired or replaced.

I hope this helps.