I have a peer to peer network that was previously running Windows 98. I replaced all PC's with new P4's running XP Prof. None of the PC's can see each other or ping each other even though they can get out on the web acreoss broadband. They can print to the network printer. They can ping the network printer, the broadband router and the broadband firewall. They can even ping outside sources. I have taken them back to the workshop and put them on my network and they can see my network, ping my network, be pinged by my network but not ping each other. I have tried all the usual stuff. New cables, new switch, disable firewall etc etc. HELP!

I'm replying to my own message how sad is that. Anyhow I solved the problem by replacing the on-board NIC in one of the PC's, didn't matter which but it solved the problem anyway.