If the service is not running, then you can start it manually. Go to Start > Run > services.msc. Locate the McAfee services in the list then right click them and choose Properties. Make sure that the service is set up to Automatic start. Secondly, press on Start button to start the service. Normally, these services shouldn't be turned off, but as soon as it starts, you should start a full computer scan to avoid any infections from malware.