This is a physical problem,it means that the hard disk's magnetic media is defective. When we run a disk utility like Scandisk and Norton Disk Doctor, such faulty sectors are marked with a "B". We call this a low level formatting. Low level formatting programs are utilities for detecting bad sectors and wiping the disk(for security reasons).These programs scan the disk, seeking for defective sectors and updating the disk's map.This isn’t actually a physically formatting of the disk.If that would be the case the servos(signals that operate as a guide for the hard disk head) would be erased and the hard disk head would be unable to move any longer.For this reason that current physical formatting programs do not actually physically format the disk.

At a high level formatting (through the Format command), the sectors contained in the bad sector table are skipped. Accordingly, there will not be any sector marked B ("Bad Block") in the FAT, although the defective sectors remain on the disk.Defective sectors are not removed, but merely noted in this table of bad sectors, resulting in the system ignoring them.We could say that the sectors are hidden.The best program to be applied in the procedure is the manufacturer's one, given on the respective utility page. If new bad sectors keep occurring after running this procedure, you should get rid of the disk, as its magnetic surface is deteriorating, for some reason.

Logical bad blocks are irregularities on the magnetic part of hdd, formed due to extensive read or write operations, caused by viruses, corruption's in the boot records, sudden voltage surges etc.The software for bad sectors remove logical bad sectors and repair your software.The Disk Repair software is a hard disk utility that can help you repair the logically formed bad sectors. Repair Disk Software realigns your hdd magnetic orientation so it can allow to read and write each byte.This way hard disk space recovery becomes very easy.