Logged In: NO

You need to check "apple remote desktop" in the prefpane for the computer
you want to browse only (lets call it COMPa).

The computer with COTvnc on it (eg COMPb) that you're using to view/
command the other one, need have nothing done to to it.

COMPa has the ARD checkbox in sharing prefs ticked and details filled out in
that prefpane (eg passsword needed to connect etc)
COMPb has nothing altereed / ticked
COMPb has COTvnc installed on it
You use COMPb to observe/control COMPa