since you've had an unsucessful uninstall of mcafee, try this.
EITHER install it again and then uninstall it thru add-remove programs or by using a good uninstaller like 'absolute uninstaller'.
OR do a search for mcafee on your pc for the remaing files. delete all such files found, manually. then use a good registry cleaner (absolute uninstaller also has one) to remove the residual invalid registry keys.