network finds computer buy cannot access it

I run a 3 computer network. 2 computers run XP Home and
this runs Windows 98. The two XP machines interact fine.
My 98 machine did, but suddenly I cannot access one of the
others. When I do a find computer test, it finds the
computer that I can't access. When I try to map the
network drive that the inaccessable computer is on it
tells me that the device does not exist on the network.
Odd because when I go to Network Neighborhood the target
computer shows up on the list.

Frustrated and wasting too much time.

Joel