Difficult to say without knowing what else is running, but it looks as if McAffee is clashing with something resulting in a slow or intermittent boot and poor reaction times.
What is the specification of your PC ?
Do you have any other Anti Virus loaded ?
What processes are running in the background ( hit Ctrl-Alt-Delete for the process manager.)
If we can't find a solution and you can't get McAfee to run properly, as a last resort try downloading one of the free alternatives like avast!, disconnect from the Internet, uninstall McAfee then add the replacement.