go into the soundcards mixer by right clickin on the speaker icon and going into recording properties....make sure line in is selected and the fader is up.......
im already familiar with most of the stuff u siad. im having problems getting a decent volume cuz i have the line in maxed out and its still really faint. on the microphone port however its fine.
im not too familiar with cubasis 2.0...is there any meters to show if you are getting a good signal going in.....you'll want to get a pretty hot signal, close to 0db but dont go over it......