Logged in on my Battlenet launcher on my new PC and it shows that i need to buy the game again but i own it. This is the right account. Account settings shows me that i have the game and everything. Why cant i download it?
It looks like your Purchase attempts for Cold War failed. I recommend removing and re-adding your payment information to your account and trying to make the purchase again. Make sure your purchase attempt is coming from the registered location for the account and that the payment method is also from the registered location.
If you continue to see issues with that go ahead and submit a ticket for direct account assistance: