Really having problems networking with XP nowdays

I am on a home network with a total of 4 computers. Now I typically run mine as .1 since I generally host the internet (slow half speed dial up). I check file and printer sharing on each computer. Now I am having a heck of a problem it seems since the updates of the past year in keeping everybody visible to each other and able to see each other not only in windows, but in games as well. When I check to share a file in My network places, it shows everybody as being on the internet. Anybody have any ideas? Oh, we are all on the same workgroup as well.