Sice a couple of days Im facing a weird problem with some hard drives in my PC. Currently, I have 8 HDDs, one is 5Tb, the rest are 8tb, and one 10Tb. We have had several power cuts lately and suddenly, a hard drive stopped working. But if I put the disk in an external dock, it works perfectly. When I put it back in its place, it starts doing a snap sound and Windows cant start. Whatever disk I put in that power cable, does the same sound. I tried changing the data cable and it doesnt solves the problem. The 3 power cables that come from the PSU (a 1000w PSU) seems to support only one hard disk. I cant tell my boss it s a power supply problem without some strong evidence, it is a quite expensive 1000w psu as I said with only 3-4 years of use, plus a secondary PSU for the video card. What can be the problem here? I really wouldn like to reinstall windows without reason.

Did you replace said HDD? Sometimes we find oddly failing drives and the owner didn't replace them.

Also, be sure to look at the S.M.A.R.T. values. If you find 01 and 07 out in the thousands (raw value) then the drive has issues. This is well discussed so I see little need to duplicate priors. If you see this, you replace the drive.

The drive snapping sound is probably the hard disk head parking. The reason it is parking might be a faulty power supply. This happened to me with a brick power supply.
If the drive works fine in an external dock, this indicates the power supply might be faulty.
Also the fact that the power supply can only support one drive indicates the power supply might be faulty.