Cannot See Main PC In Home Network

[stratcat250]

I setup a file sharing network with three computers. Actually sometimes more.
At this moment I am using a Dell Inspiron 6000 with Windows Media Center, a
Mac Powerbook G4 with OS 10.4 and the main PC is a home build with XP Professional.
I can see all pc's from the main computer through "Network Places" except the main PC. The two laptops can see each other but not the main PC. A am able to ping all machines successfully. I cannot get the main machine to appear in "My Network Places" in any of the three machines. I have been at this for days trying all the setting I can and I'm not getting the solution. Please help!!!

[aliashh]

i had exactly the same problem with one machine in a 4 m/c network. i struggled for about a week before realising it was the only m/c where i had updated the firewall plus. i uninstalled and removed traces, reinstalled and problem was solved.