Occasionally one or more sectors on an otherwise good hard drive will go bad.
When this happens, the data in those sectors may be lost, but the data on the rest of the disk will be unaffected and the disk is still completely usable.
Those bad sectors can not be repaired, but they can be marked as unusable. Once marked as unusable, the Operating System will know not to attempt to store data in those bad sectors. The total disk capacity will be decreased by the amount of storage space in those bad sectors.
If your hard drive is experiencing a bad sector, back it up immediately. If the bad sector was caused by a faulty drive head, the problem can spread to many other sectors across the disk.
How to "Repair" a Bad Sector in Windows XP
* Press the <Start> button.
* Select <My>.
* Under Hard Disk Drives highlight the disk which you want to scan.
* Open the <File> menu and choose <Properties>
* Open the <Tools> tab.
* Click the <Check> button.
In earlier version of Microsoft Windows and DOS, this functionality was built into the `scandisk` and `chkdsk` utilities.
Once the bad sector or sectors have been "repaired", continue to back up your hard drive on a regular basis. Hard drives are mechanical devices and all mechanical devices will eventually fail.
