All laptops on network perform slowly.

I have W2K AD Domain with about 40 clients. Most are desktops, but there are about 5 laptops on the network with all OS’s being either W98 or Wme. Desktops perform fine , but all of the latops are just crawling at a snail’s pace. Has anyone ever experianced a similar problem or know how to fix this problem. Any help would be appreciated. Thanks.