Computer Laptop

How do I install KASPERSKY Internet Security onto an additional computer (laptop)?
I purchased Kaspersky a while ago and installed it onto my computer and I bought the license for up to 3 computers. I’ve since installed it onto a new computer. Now when I try to activate it on my new computer (laptop) it says the Key is invalid. I’ve put in the activation code on the CD perfectly numerous times and now I need help!
You need to contact Kapersky and have a chat with them. @
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