Computer Help and Support

either a password or a key on a separate drive like a USB drive, they won't be able to replace the mobo and make the computer work again (without a fresh install of Windows), because the main point of this kind of encryption is to tie the drive to the particular motherboard in use, in essence. Can't take the drive out and put it into another computer and read it.

'The computer' ... is essentially identified by its motherboard. So for all intents and purposes when you put in a new mobo, you have a different computer.

You can't defeat this simply by toggling off TPM on the new board, that would defeat the whole scheme in a very simple and obvious way.

So hopefully they're wrong and/or you have good backups