Use the windows utility to check
computer --> right click your HDD -->Properties
Tools --> Check now (error checking section)
Click scan and attempt recovery bad sectors
The HDD firmware automatically remembers and marks the bad sectors so that the OS does not use these.

eka auto wenawa api manual karanna one na, eth ehema karanna puluwan seemawak thiyenawa. ethanin eha mokuth karanna ba.

You can use it even it has a few bad sectors. But you need to watch it by using any SMART monitoring software (lot available for free use) to see whether it develops more and more bad sectors - a sure sign of impending disaster - in which case go for another drive. All depends on how valuable your data is ;-(