Can access internet but not other computers

Have a desktop with MN-700 base station, a laptop with a
MN-720 adapter, and another desktop with the MN-710 USB
adapter. All can access internet with no problem, and all
can see each other in the Networking Utility software.
Cannot set up network however to share files, printers,
and for gaming. Desktop with base station and laptop use
Win XP Home, and other desktop has Win 2K Pro. Must be
something simple, just can't see it. Looking for help
network these computers together for other than internet.
Thanks

Rich


Richard