Avoid any links claiming to be a "PC Crack" for this specific title. They are almost certainly scams. Your best bet is to play the newer titles or look into the Xenia emulator if you have the hardware to handle it.
That said, if you're still interested in Forza Horizon 2 and exploring how it can be obtained for PC, here are some general, informative points: Avoid any links claiming to be a "PC