Do you know if the subscription for your Dell desktop has 1 license or does it have 3 licenses? If you have a 3 license subscription then you can log in to your online McAfee account and download and install the software on your Samsung. If you have only 1 license then you will have to purchase the full version.
We can't check your account from here and I have no idea how Dell licenses work, only the Customer Service people can do that. Contact them through this link, change your Country as applicable at top right if necessary: http://service.mcafee.com/CustomerService.aspx?lc=4105&sg=CS&pt=1
I believe they are only open Monday to Friday.
Have you gone to the download page of your account to check there?
Since you already have a dell – McAfee security center , you can opt to subscribe for an additional license from Dell that would help you cover the laptop even.