...may have developed bad sectors...

It used to be that whenever my W98SE PC crashed (or froze, and I had to "reset" it), early in the reboot I would get a message: One or more of your disk drives may have developed bad sectors. Press any key to run ScanDisk with surface analysis on these drives...

I would press a key, and then get a message that ScanDisk failed to run, so I'd run it from my Norton Disk Doctor after the PC finished booting. After that, restarts of my PC would not give me those messages (until the next crash/hang).

Then, several months ago, it quit doing that. This PC hangs or crashes FREQUENTLY, but I would not see those messages during a reboot following a crash/hang. Anyway, all of a sudden the messges have come back, but now I can't get rid of them. I ran ScanDisk on EVERY drive (took more than half a day because one of my hard drivesis 100GB). No time when I have EVER run ScanDisk have the results shown ANY bad sectors.

What can I do to get rid of these messages?