Is Upgrading My Old Linux Machine to Windows a Good Idea?

Hey everyone! I just got my hands on an older computer that runs Linux, but I really want to switch it to Windows for casual gaming and work purposes. The problem is, it seems like I'm hitting a wall with the current CPU (an AMD Phenom II X6 1045T) since it's not compatible with Windows 11 due to its age. I'm thinking about just replacing the CPU to make it compatible, but I'm not very tech-savvy. Do you think that's a good approach, or should I just start fresh with a new setup? Also, I'm getting warnings about my motherboard—could updating the BIOS help, and is it a straightforward process? Thanks!