SeaTools for DOS and Windows - How to Use

OK, tried that, no difference. Same result as before when I tried the Windows version (except maybe a bit quicker), but basically nothing in the "Detected Drives" window.

Does it have the ability to fix bad sectors?

I have tried chkdsk with both the /f and /r options and it did not fix the problem, this is the precise reason why I wanted to use the SeaTools program. I understood it could fix bad sectors on Seagate HDDs whereas the Windows chkdsk tool only marks them as bad I believe.

Hi, I checked the link you posted and that software sounds pretty good, so I'll give it a try, thanks.
Good job I followed the link as first I thought you had mis-spelled Easeus Partition Manager.

I'll also try the PassMark, but I have already used a SMART monitoring program (gsmartcontrol), which identified Re-allocated sectors (ie bad!) but the disk passed the basic test.

I'll let you know how I get on.

The Passmark program shows the Status of my disk as OK, however when I try to run the Disk Self Test (Short) it gets to 10% then gives the message "The last self-test routine completed with a failure of the electrical element" and doesn't get any further.

The other program you suggested, Eassos, looks really good and I was initially impressed as it found a few damaged sectors but I don't know if I really trust it because I realised that the results somewhat depended on my PCs background activities. For example a few damaged sectors were found when my AV decided to update, and then later when I rebooted my router suddenly a few damaged sectors appeared again. Also this was the second attempt, after I suspected this was happening on the first attempt, aborted at 17% and on the 2nd attempt some sectors that were marked as damaged on the 1st attempt were suddenly "Excellent", this without the Repair function actually being run (I've only done the Verify so far).

So I'm not sure whether to repair the ones found as damaged in my 2nd attempt or not, as their blurb seems to imply that the repair process is data-destructive.