Policies & scipts deleted from SYSVOL

I have a situation where the group policies & scripts directories are being deleted from the SYSVOL folder, nothing showing up in Event Viewer. MS Knowledge base has although documented it, thier solutions fail. most of our workstations are 2000 so they log on to the network but we still have some 98’s and they are denied access. we have a number of DC and they replicate this problem.