First, when you say you can't log onto the router, which one are you speaking about? Assuming that you're speaking of the DIR-655, I'm not totally sure about this, but since you're using the DIR-655 as simply a "Switch", I'm going to assume that you've already disabled the DHCP on the DIR-655 and your other Router is assigning IP addresses. This is the part I'm not to sure of as I've never had a setup like what you're doing. But wouldn't the ADSL router be assigning the DIR-655 an IP address, I mean wouldn't even the "Switch" need an IP address? And again, wouldn't the ADSL router be assigning that address? Also, if in fact it is the DIR-655 you're speaking of, that would also be the reason why you couldn't log into its web page, because it has been assigned another IP address (or at the very least it has been changed somehow). Well, I hope that this helps you in some way.