local and network registry - saving user settings?

Previously we had an ini file which told us to read the main ini on the network or on the users local machine, this way, ruiinung the app from a network, the users could either save individual settings or have the same ones. How can I duplicate this functionality with the registry. I could have a key in the network resgitry. But how can I read the users registry on their machine as opposed to the networks? A user logs onto our app with a unique userid, perhaps I should store under that userid (not a computer useris just for the app)  in the network registry? All thoughts/solutions would be appreciated. Thanks, Tom.