how to fix "bad sector"

Depends what operating system you are running, you used to be able to run scandisk perform a physical scan and edit out bad sectors, perhaps there is an utility to do the same on modern OS, try googling it all the best urban

There's more than one way. Scandisk would be the quickest and easiest, which is usually in "tools" under "properties" on the drive you want to check for errors. Another way is HDD Regenerator, which works no matter what OS you use. When it finds bad sectors, it sits there and prods them until they get re-magnetized. HDD Regenerator can usually always read the binary data even if the sector is bad, and will restore the sector to the same polarity; it fixes bad sectors without formatting your hard drive.

plz use norton disk doctor for fix bad sector.