Can you supply some details like are they all in the same workgroup, all got different names and IP addresses - assigned by DHCP?
Do they all appear in My Network places? If you "see" the printers and shares but do not have permission to access them, that can be due to logging in as a different user, share / NTFS permissions incorrectly set or firewall issues.
Have you got any firewall software running (XP or other) that may be configured differently on one PC?
I assume that you have Client for Microsoft Networks installed on the laptop you are having problems with?
MS have quite a good how to and troubleshooting section for networking with XP on their website - worth a look.
SD