What parts do I need to change?

I just bought a new motherboard and processor and now I'm going to reinstall the windows
Will hwid go? Or should I do something else?

You should be fine if this is a one off.
If you have a lot of hwid bans, just change everything, including vpn :)

don´t forget the harddrives.
Only MB and CPU is not enough i think.

I’ve seen people say new mobo, new hard drives and new windows