I can't log into my account on my new device.

In 2017, I got Minecraft on a family computer. The family computer was very old, and slow. Now, In 2020, the computer is even more slow. I recently got a laptop and I have tried at the least 10 times to log onto my account on my laptop. I can't. It's very stressful, since it's all I can do in quarantine. Please get back to me, or fix the problem somehow. (Note, I have changed the password. I also do not know the version-