You should only have one each protocol. So get rid of duplicates. Or extras thaat aren't on every computer.
Netbios over tcp/ip is in the properties of the TCP/IP protocol, advanced>under the wins tab.

The bindings are on the toolbar of the network folder>Advanced >advanced settings in XP. I'm not sure where they are in the others. http://www.wown.com/articles_tutorials/Windows_9598ME/ should help.

As long as all the computers are connecting to the router I assume your obtaining the IP automatically ,good. Share something in each computer. Share a printer. Don't be concerned when it doesn't show up in Your Network.

XP might take forever to network compared to 98 and ME. Go to folder options in control panel and uncheck automatically search for files and network folders.
Disable searching for scheduled tasks
describes a bug in Windows 2000 Professional that might also exist in Windows XP. Disable searching for scheduled tasks by deleting this registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
CurrentVersion\Explorer\RemoteComputer\NameSpace\
{D6277990-4C6A-11CF-8D87-00AA0060F5BF}