All too often, installed programs "hide" from the native windows uninstaller and/or don't uninstall correctly/completely. You need a third party solution for those.
Try using a Mac. None of the 3 buttons actually close anything. One minimizes, one sort of resizes the window, and the other one essentially minimises but is sneaky about it. You have to either right click (in some cases tap with two fingers) on the dock icon and hit quit or use the top menu bar to quit. Not a big deal but when you're used to PCs it can take some getting used to.
Unless it's one of the really shitty things that still persists as a background process.