Conflicting results from a squeaking hard drive

For some time now, I hear a squeaking sound from my Seagate HDD when reading or writing a file, sometimes when the drive is idle.I verified that it isn't a fan or a heat sink, and when that happens I get the dreaded The IO operation at logical block address 0x9468 for Disk 1 (PDO name: \Device\000000nn) failed due to a hardware error., nn changes by event.

The message above and all my research point me towards a hardware failure. So I took it out and attached it to a SATA to USB cable and tested it on another computer using SeaTools from Seagate, Partition Wizard to do a surface scan (looks like Scandisk from MS-DOS 6.22) and CrystalDiskInfo, all of these tools return an error free result.

Replugging it back and replacing the SATA cable (more than once), it might stay silent for days then the squeaking comes back. Also playing a video file results in the playing being stopped and getting 0x800701e3 error which also points to hardware error.

Any reason for these conflicting results? Am I missing anything? Is it a power problem?

The message above and all my research point me towards a hardware failure.

Agreed. The drive is on the way out.

I ... attached it to a SATA to USB cable and tested it on another computer... all of these tools return an error free result.

These tests are a point in time and do not mean the drive noise and errors can be ignored.

Any reason for these conflicting results? Am I missing anything?

I believe what you are "missing" is that the tests are a point in time.

You do get hard errors and the drive should be fully backed up immediately, and then replaced as soon as possible.