Spare sectoring, as far as i knew, is marking bad sector and tell the controller on the HDD to used another back-up sector when the head move to the bad ones, right ? And this is done in factory, to create new bad sector free HDD (as manufacture process is never perfect). And when in use, if any bad sectors aroused, zero-filling the HDD can do the same thing, remap the bad sectors to its back-up (that's what I read over at The PC Guide). But what I want to know is, is there really enough spare sectors, even for a few meg ?? Personally I don't think so, i've been zero-filling lots of bad HDD and yet all that don't seems to have any effect ??