my hard disk has got bad sectors

One bad sector does not mean the disk is bad!

Normally I allow up to 10% of all the sectors on the disk to be bad before I replace the hard drive.

What you should do is set a task to surface scan your hard drive once a week.

If the number of bad sectors starts to go up, I would think about replacing the hard drive.

The first thing I would do is check with the manufacturer to see if the drive is still under warranty. Most carry a full 3 year warranty - bad sector(s) indicate a drive that's starting to fail. If it's still under warranty this constitutes getting a free replacement.

Good luck

Just as a point of interest i have fitteed a storage drive to my system so i backed up all software and files i dont ave setup disks for ( particularly my isp in which i can only access the web through thier software that is not suplied on disk and is too big for floppy ) i downloaded the necessary software from the HDD manufacturer web site , and lowlevel formatted my C:drive , now i am back up and running again my system has never been faster , it is simple ans safe if you use the software recomended by the manufacturer and then just start all over again , but as previously said by others if your drive is new and or under waranty i would check with the supplier first , if low level formatting does not remove those bad sectors , then the drive is beyond repair , just let scan disk set them aside and work around them until it is nolonger able to do so , or use it as a storage drive and replace the main drive with a new one .
I hope that puts some light on the subject for you .