A: The legitimate iw4sp.exe from Steam or a retail disc is not a virus. However, 99% of third-party download sites offering the file standalone are distributing malware. Always verify file hashes against known good copies (e.g., from the Steam beta branch).
Since iw4sp.exe relies on DirectX 9 and older Visual C++ runtimes, new Windows installations lack these.
The Fix:
Before we proceed, a critical distinction must be made. You cannot legally download just iw4sp.exe as a standalone file. This executable is proprietary code owned by Activision. If a website offers a direct download of only the .exe file without requiring the original game data, it is almost certainly:
The only safe and legal way to get iw4sp.exe is to install the official Call of Duty: Modern Warfare 2 (2009) game via a legitimate storefront.
A: If you obtained the file from the official Steam beta branch, you can add an exception in Windows Defender or your AV software. If you downloaded it from a random website, thank your antivirus for saving you from a potential Trojan.
You have three primary options to obtain the official iw4sp.exe: