All machines are must be in the same subnet, i.e. 192.168.0.x where x is any number. The subnet mask should be 255.255.255.0 for most small networks.
Turn off any firewalls for debugging. If the firewall is the problem, you'll have to configure it to allow access to "trusted zone" addresses. Note that some firewalls must be completely uninstalled to stop them from affecting your networking.
PING each computer by IP address, and if successful, PING by name. You can obtain the IP address of a computer by opening a command prompt (DOS window) and typing IPCONFIG. This should work for any Windows version.
All computers should be in the same workgroup for computer browsing to function properly. File & Print Sharing has to be enabled on any computer you wish to share files or printers from. You also need to actually share the resource in question from My Computer, right click on the drive/printer/folder, and select sharing.
If you encounter difficulties accessing computers that are visible in Network Neighborhood, make sure the computer being accessed has an account with the same name/password as the system connecting to it uses to login.
While the default NetBIOS setting is correct for normal network configurations, it's possible for it to be altered, and it costs nothing to make sure it's correct. NETBIOS over TCP/IP must be enabled for normal network browsing.
One other thing that may help is to install NEBEUI protocol on all the machines. On everything but XP, it's dirt simple, just another protocol.
To install NetBEUI on Windows XP:
Insert your Windows XP CD-ROM into the CD-ROM drive (close the Autorun window) and use the explore option from a right click of the drive in My Computer then go the \Valueadd\MSFT\Net\NetBEUI folder.
Copy Nbf.sys to the "Windows"\System32\Drivers folder.
Copy Netnbf.inf to the "Windows"\Inf folder (hidden: change the View Settings). (Where "Windows" is the name of the folder that windows is installed in) Click Start, click Control Panel, and then double-click Network Connections.
Right-click the adapter you want to add NetBEUI to, and then click Properties .
On the General tab, click Install.
Click Protocol, and then click Add.
Click to select NetBEUI Protocol from the list and then click OK.
Restart your computer if you receive a prompt to complete the installation.
The NetBEUI protocol should now be installed and working.
If you have an OEM installation or don't have the XP CD, you can also download the necessary files from:
NETBEUI Install Files for XP