What I do is I always look on YouTube how to disassemble that particular model of laptop. Most times they have it. They you can patiently take it apart and fix it, that's if you can fix it because it might be and embedded chip that you can't fix.
I've never bought windows before. I just export the key from the old computer and put it in the new laptop. You can download windows from Microsoft. I've done it for many people, for my own laptops I just use Linux.
What is wrong with it, that you need to take it apart. If it's just bitlocker, can't you just reformat it?