The easiest way to to delete a service that is no longer needed is to use autoruns that can be downloaded autoruns here. If you have xp run it in an admin account. If you have vista or win7 right click and run as administrator. Then, click on the services tab and see if you can find the Mcafee service. Then just delete it. I used it to delete a service that a2 anti-malware free left behind when I uninstalled it.