Cubase killed my audio line input

I was recording voice overs in FCP. I use a mic into a mixer (which provides phantom power for the mic) and into a compressor then into audio line input on my Mac Pro. Recording went well.

Then I installed Cubase 5 that came with my Zoom H4N. After a long process, it recorded through USB but now my line audio input no longer works.

I tried Midi Setup in Utilities, I trashed preferences, reinstalled Cubase -- nothing worked. I know the mic/mixer setup is working; I tested it in my Mac Mini. I have tried different cables, different mics, nothing works.

In Sound in System Preferences, I get no input at all.

What else can I try? I would like to completely unintstall Cubase, but there is no utility for that.