Assuming you have found a reputable source, here is the general process for installing a highly compressed PC game like MW3.
"Highly compressed" game downloads from unofficial sources are almost always: Assuming you have found a reputable source, here
Legal alternative: Call of Duty: Modern Warfare 3 is available for purchase on legitimate platforms like Steam, Battle.net, or physical PC discs. It often goes on sale for very low prices. Legal alternative: Call of Duty: Modern Warfare 3
This is the most critical section. Call of Duty: Modern Warfare 3 is a commercial product owned by Activision. Downloading a "highly compressed" version from a non-authorized source is technically piracy unless you own a legitimate license for the game. This is the most critical section
Here is the distinction:
Disclaimer: This article does not endorse piracy. However, we understand the curiosity and will guide you on how to approach this safely if you choose to explore compressed game downloads.
Title: Call of Duty: Modern Warfare 3 – The Definitive PC Experience Genre: First-Person Shooter (FPS) Developer: Infinity Ward / Sledgehammer Games Release Date: November 8, 2011