When I built my system in 2011 I put two WD Black 640 GB HDD's in. One of them lost it's NTFS status and was showing as "RAW." I tried chkdsk on it, and it showed errors, then said it fixed them. But another sweep showed the same errors, again.

I was able to extract almost all of the data using Testdisc, a free command-line-based disc utility, and put it on an external drive. Then, I was able to wipe and reformat the WD drive. Then I copied the data back to it. But upon comparing the source and the destination after the copy, some was missing. I ran chkdsk on the drive, again, and it showed the same thing. Errors that it said were fixed, then said weren't fixed. I downloaded a WD utility, which did a real slow analysis, but it couldn't fix it, either. My understanding is that "fixing" it probably means marking bad sectors as not usable. Whatever. No love.

Nothing's working to fix the drive. I would just go on using it, but I'm afraid it'll go RAW on me again without notice. Or some other kind of bad thing will happen.

I'm planning to replace the drive, but -- any other ideas on how I might make it usable/trustable, again? Are there any better utilities I could try? Not interested in spending much, as you may imagine. Free is good. But I know that you usually get what you pay for.

Thanks for any insights.