Hiyas,
Hey Snake, welcome back

Glad to see you're still at it. This stuff is just way too much fun to give up for long isn't it?
I think the easiest way to find out what control or window is holding the Ad is to use the direct approach with a Windows monitor like WinShow/Winfrog or Windowse. Point it to the Ad window and this will give the Class and Hwnd.
Then type 'Task' in Softice to get the modulename and 'Hwnd <modulename>' to get a listing of the controls making up the active window(s). All this really does is give you a handle (so to speak) on the hwnds of the program. Kind of useless unless you combine it with other information like APISpy output monitoring creation of the Ad window. Just match up the hwnd of the Ad window with whatever API calls use it and see if you can short circuit its creation.
If you want to try the techniques I used in Frazzle to get rid of the Ad banner, and move and resize other controls by altering the params pushed to CreateWindowEx, ShowWindow, SetWindowPos, give it a shot with the Opera 5 Adware. It will work exactly the same way, heh, heh
I took a quick look at Kazaa. What an obnoxious adware program, wanting to install all these extra demo programs! I'm not too sure about getting rid of the ads in this one because they all seem to be within the main window, an Internet Explorer_SE Class. Essentially they're ads within a web page, so I don't know if you have any control over them in the same way.
Hope this helps,
Cheers,
Kayaker