The thing to do is if you already haven't uninstalled all the files you need to search the harddrive for mcafee and include in the search all hidden files and dir.
After doing that you have to run regedit and use the option find type mcafee and delete all with mcafee except from the security center(Microsoft not mcafee, remember microsoft also has a security center). Remember to use F3 and delete while doing this, because it will take about 10 mins to do this, this way. Also you will probably need to change permissions on some registry parameters, this you do by right clicking on the parameter and change the permissions.
After that you need to check again if there are any files of mcafee on your laptop the same way as described above.
If you havent uninstalled all mcafee because the uninstall app was faulty, then you have to go to mcafee.com on the help pages to get the manual uninstaller for all mcafee programs you have in the mcafee security center. Use those to uninstall and then start on what I described above.
Try using Panda Software(Thats what I use it is GREAT
) to check if mcafee is gone, you can download it for free on their internetsite: www.pandasoftware.com/
If you can install this program mcafee is gone! If not, then start again with search computer to delete all mcafee files and start off with the regedit again!
After about 300 mcafee deletes(or more) the stuff is gone!
Hope this helps! I did it this way and it was a very very time consuming experience! NEVER MCAFEE AGAIN! NEVER EVER!