Win XP Home Ed. network

Have anybody run into this kind of problem:
3 PCs w/WinXP Home each, P-to-P network, IPs – in auto, each PC has it’s own dialup. Before the network each one of those PCs could connect to and send/receive e-mails from one of the web servers(not their ISP), but now neither one can send through the non-ISP server – only receive. While can do both to/from their ISPs e-mail server. Am I missing anything?
And the other thing in the same configuration: dialup on each PC would come on on its own without anybody’s input for it. Can correct tis by disabling Universal PnP service, but in this case – no dialup at all. And some more stuff disappeared. So, that didn’t work good… Could anybody help please??