I'm trying to install Norton Internet Security 2011 and it won't let me get past the Product Key. I entered the Product Key that was on the yellow sticker insert from the package and the "Agree and Install" button will not activate. There is still a red "X" on the right hand side of the box where you enter the code. I've tried typing it in and double checking it several times and I'm not missing any characters because it will not allow me to type anything else in. Very frustrated.