Fitted broken laptop components into another laptop but can't access files


TS Rookie
I'm hoping someone can help me with this issue!
I removed the entire contents of my broken laptop and fitted into another laptop.
It starts and Windows (10) seems to work BUT I can't see Users or my folders and files in C drive!
I can see some of the files in Quick access section but when I try to open, I get this error message
Can anyone offer any guidance as to what steps I need to take to be able to access my c drive as I could in the old laptop please?