I would suggest trying to uninstall it with the "Revo Uninstaller". The FREE version should do it. Have Revo remove anything Yontoo-related. There is no harm in trying it.
Depending on the browser your wife is using, you might want to first disable (or remove) any Yontoo Add-ons or Extensions.
Best of luck..
My wife is using Windows 7 Home Premium with SP1. She got an alert from facebook (and she says she never allows apps and never plays games on fb - it's probably true cause she's see me harp on it so much) that she needed to uninstall the program noted above.