Ok, I've searched high and low all over the internet, including this forum, and can't seem to find the answer to my problem. I have two computers: - Windows XP Pro SP3 - Windows Vista Home Premium SP1 XP is wired directly into my D-Link WBR-1310 router, while the Vista machine is on WiFi. Both can access the internet through the router perfectly fine. They are both on the same Workgroup and File and Printer sharing is enabled, Vista is on a "Private Network", both have folders setup for full access sharing (read and write). I've tried installing Layer Topology Discovery Responder in XP, but it says a newer version is already installed. I'm guessing it's included with SP3? I can see both machines with IP addresses in the Network Map in Vista. I can ping the XP machine from Vista, but XP can't ping Vista. Neither have firewalls installed/enabled. My router shows both of them connected to it with their IP and MAC addresses. I'm running Avast! Home edition on both machines (no Norton crap for me thanks). Aside from the one-way ping, neither machine can see each other? What am I missing???? PLEASE HELP! Thanks

If you have put into manual some of the services, which otherwise have configured to start automatically by default, in an effort to speed up your PCs, that could be one of the reasons. This is something I do frequently and then try the hard way to correct. TCP/IP netBIOS helper service is the one I have found necessary to have proper networking. Check it and it should be on Automatic on both PCs. By the way, I have the same configuration as you, namely, a Win XP Pro SP3 machine connected to the modem/router through Home Plug and another machine with Vista Home Premium SP1 connected to the same modem/router through Wireless. The second machine uses files and USB printer connected to XP machine. Hope the above helps. Regards SuatCINI

SuatCINI: Thanks for the tip, I do actually play around with the services to try to optimize performance, but it seems I haven't touched that one. It's still set to automatic. Any other ideas?

"but XP can't ping Vista. Neither have firewalls installed/enabled." You have to be mistaken. Only a firewall blocks ping. Re-examine Vista's firewall. It should be configured to trust the xp host by name. Make sure in tcp/ip advanced properties/wins tab that netbios over tcp/ip is enabled. Post a ipconfig /all from each pc for examination. McCain: steal from the poor/middle class and give to the rich Obama: steal from the rich and give to the poor/middle class. Go Obama!