New PC or new Windows

Hello, a known one of me has problems with his PC and Forza Horizon 4.
Unfortunately, he can no longer play FH4 on PC because he does not get connectivity for online sessions.
However, this works on the XBox.
He suspects that his PC has been blocked, but he does not know the exact details.
Unfortunately, he gets no answers from the support.

He asks if it makes sense to reinstall the Windows or to get another PC.
I think if the game works on the XBox, it would have to be on the existing PC … So Windows New or hardware New, no idea …

Many thanks for your help