I would try HD Tune, and look for SMART errors as well, don't know how old the drive is but at 160GB it's probably on it's last legs, time for a new drive if it's old and now starting to have errors. Back up your data, buy a newer drive (larger) and image them.
a "TRUELY" bad sector can NOT be repaired, what programs do is remap the bad sector and Map a "spare" sector inplace of the bad sector. HDDs contain a Hidden extra sectors for this purpose. This is OK untill you run out of the spare sectors at which time it just marks it "BAD" and decreases available HDD space.
You can Not mark a single sector as Bad, what happens is that the cluster (Made up of eight sectors) is maked as Bad. Sector = 512 Bytes, cluster = 4 KBs normally (default)
As Noted by canadiam69 Highly recommend you replace before drive fails and you CAN NOT retrieve any of the files.
Using programmes like Microsoft CHKDSK and ScanDisk can result in more problems with your drive. Also, if you attempt to extract your data the progress bar may indicate that it will take several hours or days. In these cases the time is allowed for the system to make multiple attempts to read the drive which can cause it to degrade further. The best chance you have of recovering your data is if you take your drive to a data recovery specialist and allow them to examine it.