All say pretty much the same thing.
More of the same
See what others say before proceeding. A second opinion should be considered. Maybe a 3rd, and 4th as well.
Also your hard drive manufacturer may have diagnostic software at there support site to confirm this.
chkdsk found bad clusters on my HD, and replaced them. Am I right to understand that this refers to the file system, and no harm has happened as compared to bad sectors being found, where a defect has been discovered, which is marked so that no further data can be written; in which case, free space will be reduced (e.g. when I delete the partition and then recreate it) ? Thanks.