Open Internet Explorer and login to McAfee account using the link https://home.mcafee.com/Secure/Protected/Login.aspx?ErrCode=PLEASE from your new computer.
Under the My Protection Products section, select the subscription from which you would like a license released.
Find the name of old computer click the Deactivate button to the right.
After you have successfully deactivated the license, click on the download button and start downloading and intall McAfee. ( How to install McAfee )