Wed Nov 23, 2005 11:55 pm
Using winbox - goto a Terminal window and press ctrl-x this will put you in safe mode, if you break the router it will roll back the config to before ctrl-x
as ofasa said remove the IP address from the PPPoE interface, then only people who use PPPoE will get a connection.
Once you are OK with your router changes go back to the terminal window and press ctrl-x again to commit your config.
For more help you must post your config for interfaces, IP addresses, firewall rules etc.