How to repair bad sectors on hard drive (HDD)

Bad sectors can cause data loss on your hard drive. Thus, make sure that you do have backed up the data written on the sector before you take repairing steps, and stop your computer to continue writing on it.
Way1. Repair bad sectors with Windows built-in tool

1. Go to "My Computer", and choose the disk you want to repair. If you don't know which one, you can fix them all one by one.
2. Right click on the disk, and choose "Properties". Then go to the "Tools" tab.
3. Under the error-checking, hit "Check now".
4. Check "Scan for and attempt recovery of bad sectors" and click "Start".
It generally scans and repairs bad sectors simultaneously. When it finished, the bad sectors are repaired. By the way, if you want to fix file system error at the same time, you also can check the option. There may be a situation that it reminds you it can't be repaired because the disk is using now. Usually it's disk C: where your operating system installed. Then you can choose to repair it automatically when you start your computer next time.