Switch Minecraft email?

I have had an e-mail since 2014 that has stopped working this year, but I was still able to log in and play with it until mid-2020. Since I got my new PC it doesn't work anymore and I wonder if there's any way to change this email because I had already spent a lot of money on it and it would be a shame for the worlds. Does anyone have an idea who to write to or something?

The single player worlds are saved on your PC. You don't need the account for this.

For Windows (e.g. Cortana or in the Explorer folder) enter:% Appdata% → Roaming → Minecraft → Safes

How much did you spend money on it. For ranks?

Your email should be valid regardless of the device. Login problems can hardly have anything to do with the new PC.

If the launcher doesn't start already. Then Java can be the problem (I once had).

Thanks, so the problem in general is that I can't log in, or my "password does not match", but I have been using this for years without any problems. And yes, I've spent a lot of money on ranks and it would be a shame