There are a couple of items that can be classified as 'zango' from a game site, to an Instant Messenger type program, to a pop-up that you can't seem to get rid of (note the ETrust link).
Depending on which one you have, the various suited programs you use may see a few of them, if not all of them, as 'legit' programs that you gave permission to install.
Check out Add-Remove Programs to see if it's listed there anywhere and uninstall from there if you're able to. I suspect you have the pop-up one that fooled you originally into thinking it was a Norton alert or MS alert window that Etrust mentions.
As for the spywares, you can go to http://www.lavasoftusa.com and get the free AdAware program they offer (under products, then Free) and let that program uninstall them for you. Once you install AdAware and open the program, check for updates first and then run it.