Bad sectors are a sign ... and it isn't a good one. You can expect the bad sectors to multiply over time, with what speed ... it all depends on your hdd drive and how much you'll work it from now on.
What can you do is this: 1 prepare your self for buying a new drive, a don't wait until it is to late, I suggest you buy it right now, and use the new drive as primary and the "bad drive" as secondary, storing only the non essentials on it.
To undo the damage is almost impossible (only if buy luck the software reported wrong), but just to be really really sure, use a diagnostic software, something like Norton Utilities (Disk Doctor). Scan, diagnose ... and see if you can isolate the bad sectors (this will buy you time until the hdd fails).
The utility is from Red Hat Linux. If memory serves, a couple of months ago Perfect Disk told me to run a 'check disk', while I was defragmenting my XP partition. I guess that was my warning sign there.
Been looking for an excuse to get a new WD 1Tb HD. I guess this will twist my arm into submission.