Having issues pinging my PCs on my network

[howardq]

I have 3 PCs and a network printer connected on my Linksys DSL router w/4port switch. Each PC can ping the printer and DSL router but it cannot ping each other. I enable Netbios on each PC but that still didn't work. I can see the PCs on my Network Places but I get a request time out when I try to ping their IP addresses. All PCs can get out to the Internet
Please help.
Thanks.

 

[bcastner]

This is almost certainly a firewall issue.

. watch out for the XP native firewall if using this OS
. watch out for "hidden" firewalls in antivirus programs. PC-Illan is famous for this if installed with default settings