No, it is not necessary to reinstall.
But, you must have an account at mcafee. If not, please register there first.
Then go to "https://home.mcafee.com/root/ECards.aspx?affid=0&pkgid=276,277&flow=cdkey&cid=78 242" (without the " )
There follow the instructions. in one of the steps you have to enter your account.