Windows 7 Refuses to Work in Boot Camp on OS X Mavericks.

I was recently donated a MacBook Pro ‘13 (Mid 2014) and used it with OS X Mavericks and later upgraded to macOS Big Sur. Before the upgrade, I installed Windows 7 via Boot Camp and it worked perfectly. Today, I downgraded back to OS X Mavericks and tried to install Windows 7 again, and it refuses to work. I found the drivers for my MacBook Pro online, applied them, and nothing changed. Any an all help would be greatly appreciated!