Bad sectors can mean many things to a hard drive. Are they death knells? Or simple glitches? Read on to find out and learn how to fix them (hopefully).
First, recognize the common causes of bad sectors. Sometimes, a sector just goes physically bad. This means it just won't work anymore, and there is no way to repair it. It's common, and expected, but if you get enough the drive will become unusable and you'll need to replace it. Two other causes are simple drive instability or incorrect mapping; formating usually solves both of these (though not always).
Step2
The first step is to run the CheckDisk utility (chkdsk from your command prompt). This will locate the bad sectors, and mark them as such. It will, if possible, move the data from the bad sectors to good ones. Then, in the future, your system just won't use the bad sectors. If the utility tells you that there were several thousand bad sectors, your hard drive should be backed up and replaced as soon as possible.
Step3
It Step 2, doesn't solve the problem, back up your existing data and start clean by reformatting your drive. This should fix any 'cosmetic' damage.
Step4
If Step 3 didn't correct any problems, that your drive has sustained physical damage. There is no way to repair physical damage and restore data lost as a result. The drive must be replaced.
Step5
If you hear an kind of clicking, scratching or rough whirring noises (aside from the ordinary hum of the disk) you should back up and replace the disk. These are all signals of physical crash. These can happen a few sectors at a time, or take the entire drive at once.
Tips & Warnings
If you start to see problems arising with your drive, back up immediately. Once damage has been sustained, the data held in the affected areas will be unreadable.
Physical damage has a nasty tendency to spread. The failure that caused the initial damage will probably happen again, in a more catastrophic way.
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