On the XP box(es)
start->MyNetworkPlaces
"Set up a home or small office network"
next
next
"This computer connects to the internet ..."
Enter a computer description
Enter a computer name
next
Enter the E-Smith workgroup name -
With default server setting, browse to
http://192.168.1.2/e-smith-manager Click on "workgroup"
The entry listed in "Windows workgroup"
copy/paste into the entry on the XP box
My advice is to use all lower case workgroup names
MS does not properly respect UC/LC
next
MS will do stupid graphics now.
After computing one of the choices will be
"I do not need to set up other computers" or something like that.
Then in IE
Tools->Internet Options->Connections->Lan Settings
Turn off "Automatically detect settings"
OK
OK
Exit IE
Restart IE
Tools->Internet Options->Connections->Lan Settings
Turn on "Automatically detect settings"
OK
OK
See if you can see yahoo now.
Turning off the on autodetect seems to clear out the bad connection so MS/IE re-establishes connection information.
Then go do the same to the other XP box.
Hope this works for you. It does for me.