I just got a macbook pro and I can't use hostnames between mac and pc's. If I try to ping the mac from the windows 7 (x64) machine: C:\Users\Eddie>ping Eddie-Mac Ping request could not find host Eddie-Mac. Please check the name and try again. Similar from the mac to windows 7. However, if I try and ping using IP addresses, it works perfectly fine. Yes, I have re-installed bonjour on the windows 7 box. At least, I believe I did -- trying to find a standaone bonjour installer is impossible. I went to "programs and features", clicked on bonjour, and uninstalled it. Then I ran apple software update, and it wanted to update itunes, safari, and quicktime, (it didn't mention bonjour). I let it update, and now Bonjour is back in the "programs and features" list so I can verify that bonjour was reinstalled. I have rebooted both machines. I don't know what to try next.