Hi Mike,
Welcome to Amiga dot org!
It's good to see new Amiga owners here seeing what it's all about.
Unfortunately you won't be able to run OS4 on your Athlon as OS4 is PPC and thus will (so far) only run on PPC equipped "classic" Amigas (A1200, A3000, A4000) or the Amiga One which is supplied with either a G3/G4 CPU.
However, you can run WinUAE on your Athlon to emulate the classic 68k based Amiga line, or run AROS.
