Hey Mskup,
When you set up the network it's a good idea to use Windows XP home network setup utility.
It should be at Start, Control Panel, Network Connection, On top left
Just for elimination on almost any home network even if you connect the computers together and set File and Print Sharing on the LAN (NIC) connection they won't allow you access till you share out some folders or files.
Additionally on Windows XP you have to run the Home Network Setup to get the option to Share this folder on the network since putting it in the regular shared documents just allows other users of that computer to use the files