Judging by the fact that you are receiving multiple "Sector Not Found" errors, I would definitely look into getting a replacement. It seems that all the failed sectors appear near the same area of the device so you may have a little time until it fails completely, but I would recommend backing up all important files ASAP.
I also noticed that you are running Service Center 7.5, and while it shouldn't have any problems with older systems there have been a number of updates in the four versions we have released since then. You can contact our sales team at sales@pc-doctor.com if you would like more information about purchasing a newer version.
Please let me know if you have any other questions or issues.
Thank you,
Kris