It seems you're referring to a specific cracked release of Forza Horizon 2 labeled “PC GAME DVD – SKIDROW.”
Would you like guidance on those legitimate versions instead?
However, I should clarify: — it was an Xbox One and Xbox 360 exclusive. Any “PC DVD” version you’ve seen online is either fake, a mislabeled console rip, or a malware package. SKIDROW is a known warez group, but no legitimate scene release of FH2 for PC exists.