SpinRite!

Victoria - An experimental program to work with HDD. Victoria is a small application designed to assess performance, test and perform minor repairs to your IDE drive and SATA HDD. It's designed primarily for HDD repairmen in stationary conditions and is not intended to test the system hard drive. However, compared with the DOS-programs, the utility for Windows provides the following benefits:

Detect physical bad sectors on a hard disk drive surface. Repair physical bad sectors (magnetic errors) on a hard disk surface.The product ignores file system, scans disk at physical level. It can be used with FAT, NTFS or any other file system, and also with unformatted or unpartitioned disks.Starting process directly under Windows XP / Vista.Bootable regenerating flash can be created from the program and used to automatically start regenerating process.Bootable regenerating CD allows starting regenerating process under DOS automatically »

MHDD is the most popular freeware program for low-level HDD diagnostics.

DiskFresh is a simple yet powerful tool that can refresh your hard disk signal without changing its data by reading and writing each sector and hence making your disk more reliable for storage. It also informs you if there are any damaged/bad sectors so you know the right time to replace your disk. The best part is, unlike other tools it does all this when Windows is running and it does not interfere with the speed of your work at all.

HDAT2 is program for test or diagnostics of ATA/ATAPI/SATA, SSD, USB and SCSI devices.

DRevitalize is a program that repairs bad sectors (physical defects) on popular magnetic media (hard drives and also floppy drives to some extent) by generating a special sequence of high and low signals around the physically damaged area. The surface of almost any drive can be repaired with this utility (even hard drives that were dropped down or exposed to strong electromagnetic fields). For more informations please read the full documentation.