Best you call customer support and ask them maybe you can restore the laptop to as delivered state if this is an option and activate McAfee then uninstall it but customer service should be able to assist you
If your are using windows 8.1, you will see "McAfee Central" on your metro mode panel. All you have to do is to right click on it and choose uninstall. You may also go to your Programs and Features (..keyboard short cut = Window logo + X and then F..) try to look for any McAfee icon in there and uninstall them. (find for McAfee Security Scan Plus if it's present and then remove it)
I am definite that you already get rid of the McAfee Anti virus software traces on your computer if you already ran the MCPR (McAfee Consumer Product Removal tool) successfully.
Note: Running MCPR will get rid all of the McAfee Anti Virus software traces .
It is not going to mess up your system.
You may call McAfee technical support for assistance in the future click Services and Support for Home and Office
Hope this fulfill your query,