Just download Minecraft?

Hi, I got a new PC and wanted to install Minecraft on it. I have an account for years and only need the client to download it. But in all its ends, the thing tells me that I should buy the game again, and if I download the installer from the minecraft.net page, I can only play the demo afterwards. What should I do?

Then you probably did not buy an account or your account was stolen. If you can play the demo it means that the account was registered at Mojang but does not have a valid Minecraft license. Please contact Mojang Support.

Try logging in to mojang.com with your login data https://account.mojang.com/....com/login

There you would if your account is still valid in about the following can see.

If this is not the case, you should get in touch with support and have some proof of payment.

If there's something like this you can assume that everything is right with your account and you should be able to play.

Alternatively you could use an alternative launcher like FTB or Curse or MultiMC and check if you can play.

How Minecraft was taken over by Microsoft, you had to transfer the account. Maybe you have not done that yet?