Welcome to the community!
Do you have more information about the error message that you get? Any supporting information like the error message or may be a screenshot of the error message should help us here.
In the meantime, I would recommend that you contact our technical support team for immediate assistance. You can contact our technical support team over an interactive chat support session. Click the link below to connect to our technical support team.
Norton Forums Moderator
Here is the Symanrec support KB for that error: Error 9999,17x when Installing . Please follow the directions on this page to correct the problem. Let us know your progress in solving this problem.
I would go with Yogesh's suggestion on this one because 9999 series of installation errors are not prominent in N360 3.0. This is because we are using our proprietary installation technology in N360 3.0 instead of leveraging on the MSI.
However, if the you want to use N360 2.0, db's suggestion will be the way to go.
Let me know the exact message for the Product key. If the problem is happening after installing Norton 360 3.0 and during the activation, we can resolve it easily. If you get the message that "Invalid Product Key" or "You have exceeded number of installations..", then contact the Symantec Technical Support through this LINK, chat will give you immediate response.