I remember somebody that came to my shop ask me the same question. I told hem the other os might not be able to reconize win98. Back in they day the only way my buddys and I could get win98 work with xp is to create back up floppys.
I have recreated my account, but that didn't change anything.
I have also taken a look at my network settings under the System Policies part of the registry, but nothing seemed out of order there.
Sorry to hear that, have you tried to use a registry repair tool, doing a quick google there are quite a few free tools to use. Im still convinced that it might be a corrupt registry.