BleepingComputer.com: Question About Hard Disk Software

I have learned to defrag my pc a few years ago, and I saw a software recently call HDD Regenerator, which it claims to repair the bad sectors of a hard disk"Ability to repair physical bad sectors (magnetic errors) on a hard disk surface", is that actually true? how can software repair hardware? has it got anything to do with defragmentation? and windows has its own build-in function to repair bad sectors, are they the same?

sorry about the number of q's

I've only seen this used once, but it appears to work by reading the structure of the hard drive and rewriting each bit of information to "regenerate" the data.

This is sorta like an overwrite of all data on your hard drive with the exact same thing - it'll sort of "refresh" the drive.