Paid subscription, product fails to install

Purchased the Family Pack a few days ago on recommendation from various magazines. Installed fine on the win 10 desktop pc, but won’t install on the laptop. Laptop was win 8.1, tried installing bitdefender, but gets as far as the “preparing your computer” screen, then exits. Upgraded laptop to win 10, and still get the same problem. Have never had an AV product fail to install and have reverted to avast on the laptop. Any suggestions on how I can get, the product I’ve paid for, onto the laptop?