Home Network problem

Trying to network PC (Win XP Pro)and laptop (Win XP Home) using cable modem and switch. PC can ping laptop but not 127.0.0.1. Laptop can ping 127.0.0.1 but not PC. Subnet masks are both 255.255.255.0 and gateway is same for both. Cannot access files from either. Workgroup visible but not accessible. “You may not have permission to use this resource…The list of servers for this workgroup is not available.” Also using Norton System Works and Firewall but allowed access for each IP under Access Rules.