If this is in regards to the registration of mIRC, the change from DSL to FiOS should have no bearing, however, if it has, then you can get your registration information by going to
RegLost and there is an option there for you to have the information sent to a new address if you don't have access to the old address any longer.
However, if this is for any registration/authorization on a specific network, you'll have to contact the representatives of that network. If you can connect to the network, try #help as the standard help channel.
