waht type of surface scan? scandisk?
There are two ways to mark a part of the disk bad, one is at the file system level and the other is at the disk level.
All modern disks (an ything made within the last 3 or so years) have a set aside region of the disk and if a sector goes bad it is automatically remapped to the region set aside.
No information is usually lost and the disk continues to work as normal without your operating system ever knowing what happenned.
Sometimes you might notice that for whatever reason a sector or better yet a cluster has been marked bad at the file system level. This means that the operating system couldn't read from that cluster and after a few unsuccessful attempts marked it as not to be used.
The best way to try and reclaim these parts of disk is to wipe the disk, or in other words fill it with zero's. This is also sometimes called a low level format.
This will erase all data on the disk and will bring it back to its factory fresh setup.
You will then have to partition and format your disk and install an operating system.