Even if you get it running, many compressed mods trigger antivirus false flags. And if you try to play online, official servers and modern clients like Call of Duty: Modern Warfare Remastered won’t accept tampered files.
While I cannot directly link to pirated content, the following groups have historically released safe COD4 repacks: call of duty 4 modern warfare pc download highly compressed
Problem: Game crashes on launch.
Fix: Run iw3sp.exe (singleplayer) or iw3mp.exe (multiplayer) as Administrator. Also install DirectX 9.0c and Visual C++ Redists (2005–2015). Even if you get it running, many compressed
Problem: No sound or low-quality audio.
Fix: The repack likely downsampled audio. No fix other than downloading full version. Even if you get it running
Problem: "Error during decompression" (CRC mismatch).
Fix: Your download is corrupted. Re-download using torrent with forced re-check, or try a different repack.