wireless network file sharing problem

hi, i have 2 desktops both running xp home and one laptop
running xp pro, i am having trouble my dektop are able to
see all computers on the network but can only access
files on the other desktop.when i click to explore the
laptop i get a msg saying that the server(the laptop) is
not accessible on the network. and so i cant access files
on the laptop. also when using the laptop i get a msg
saying "(mynetwork)is not accessble. you might not have
permission to use this network resource.contact the
administrator of this server to find out if you have
access permissions " when i try to view the other
computers on the network. if anyone can tell me how to
configure.

thanks for your time