I have had my home network set up and working for months. All PCs (6 of them) are running Windows 7 Pro or Ultimate - two are wired, 4 are wireless. This is NOT a Homegroup, but simple peer-to-peer. I have a Qwest-furnished modem/wireless router, which I was using as the DHCP server and modem, but had the wireless turned off, as I had a fairly new D-Link wireless router before I switched to Qwest, and wanted to continue using it. This setup worked fine, as I said, for months. To summarize, the setup was: Qwest modem/wireless router, doing the DHCP serving, but with the wireless disabled. Wireless was being done by another (D-Link) wireless router. The D-Link wireless router began acting flakey, and was dropping connections regularly, so i decided to turn off its wireless and start using the Qwest router's wireless. I set it up just like the old D-Link router. I made no changes to any of the PCs on the network, except to reboot to get refreshed IPs (even though the DHCP server was not changed). After several minutes, some PCs finally could "see" some other PCs on the network, but mostly, there was no network connectivity. Shared printers were reported as "offline." This was yesterday. I figured by today, the network would be happily communicating. But no... One of the wired PCs sees most others, but those others don't "see back." Most PCs see only themselves, or maybe one other. Again, I made no changes to any of the PCs. The only change was to use a different wireless router. I use Windows Firewall, and either AVG Free or MSE antivirus on all PCs. What am I missing?