Windows XP Pro login problem on network

I have three computers connected together through Linksys 4 port 10/100 Router. They are running in peer to peer network. One computer is running Win 98SE and the other two are running Win XP Pro. I am able to map both way on Win 98SE and one of WinXp Pro. Both of those computer can map to third computer (Win XP Pro) with no problem. But third computer (Win XP Pro) can not map to 1st Win XP Pro. Whenever I try to map the 3rd computer (Win XP Pro) to 1st computer(Win XP Pro) I get a window asking for password as Guest user. Each computer have the same users account with no password. When user name Raymond is logged in on 1st computer (Win XP Pro) I used the same user name on the 2nd computer (Win XP Pro). Yet it asking for passwork as Guest. I do not recall enter any password as a Guest user. What I need to do to fix my problem?