So do you mean you don't know how to find the control panel in 8.1 or you can't find McAfee listed in the Programs and Features list to uninstall?
Because with 8.1, the former is simple, you can just right click the start button and control panel will be on the list. You can also press Windows Key + S to pull up the universal search bar and start typing in "control panel" and you should see the control panel in the results. The other way involves making sure that you have administrative programs showing on the start screen, so when you go to the full listing of programs, it shows things like the control panel.
If it's not showing up in the list of installed programs, that's a different issue entirely.