XP to XP problems

I am trying to get my computers to work together. I have my movie files on my computer and I want my kids' computers to be able to access them. I first set my daughters up without incident, but my son's is a bit problematic for me. I have been searching for days now and can't seem to find a solution to my problem. Mostly what I have found is that the users have to have the same account and password on each computer. My daughter's computer only has one account, for her and my computer has one account, for me. So I figured I would try it with my son's. I added a dummy account to both computers and logged into both but couldn't access one from the other. I found another that referred me to the NET command stating that all you have to do is type net user guest active:yes. I tried that on both computers and now when I try to access my son's computer a log in windows appears with the "Guest" account grayed out so I can't select any other accounts, but it is requesting a password. I have no password. So I figured why not do the net command with my dummy accounts on both computers, but nothing changed. So then I tried the net command on the guest account with active:no on both computers, but nothing changed.

I am already bald, but if I had hair when I started, I would be bald now, please help!!