Ah, the old "browse" problem.

First of all, check to see if you can connect to another computer on the network by name.

Go to the Start menu, select Run, then type two backslashes followed by the computer name. For instance, on my network, my computer is named MONKEYBRAINS and you would access it by typing \\MONKEYBRAINS into the "Run" box.

If that works, it's a browser service issue, and to be honest, those seem to kind of come and go on ad-hoc LANs and I've never seen a solution. Happens to me at LAN parties all the time.

Oh, and make sure none of your computers have goofy characters in their names. Letters and numbers only, no spaces etc.