I ask, because if you don't share any drives or directories you won't see anything.
Try sharing the whole C drive on one of the machines - ignore the dire warnings about not sharing the root of a drive for the moment, and go ahead.
You should now be able to see this drive in My network places. You'll obviously need to check that you have the correct networking protocols installed on each machine - TCP/IP, File and printer sharing for Microsoft networks, and Client for Microsoft networks. If you don't, you must add them.
Once you have the network running, with each machine seeing the others' shared resources you can fiddle with the sharing - whatever you do, don't go online with the root of a C drive shared.