How about creating a new user and seeing if the problem persists. Jens On Feb 16, 2006, at 3:32 PM, Michel Treisman wrote: > I have a 17" AlBook which I have just upgraded to 10.4.5 - but > that's not the issue, I had the problem (see below) on 10.4.4 too. > > I use a netgear DG834G router to go online. When I am at my desk I > plug the ethernet cable into the AlBook and turn Airport Off. > When I am elsewhere I use wi-fi. > At my desk, using built-in ethernet, the internet disappears at > arbitrary times: I get the message "You are not connected to the > internet". > > So I open System preferences/Network and it tells me that I am > using DHCP. But the IP Address, Subnet Mask, etc have disappeared. > I click 'Renew DHCP lease' but it does me no good at all. > > The puzzle is, if I now turn Airport On, I am on the internet > again. Turn Airport Off, built-in ethernet is not working. > > So I put a Pismo on my desk, side-by-side with the AlBook. If the > AlBook tells me "You are not connected to the internet" I switch > the ethernet cable to the Pismo. No problem now! the Pismo is on > the internet. > > Suddenly, after up to 60 min of this kerfaffle, Network Preferences/ > Built-in Ethernet fills up with my IP Address, Subnet Mask, etc, > and I am online again and the problem is over. > > The problem can't be the router - it works with the Pismo. There > is no problem with wi-fi that I can't handle by turning Airport Off > and On again. > > So what should I do next?