How to Fix IW3sp.exe on "Call of Duty 4"
IW3sp.exe is a computer file that executes every time you try to play "Call of Duty 4" on your PC. This file is not present in the PlayStation 2, PlayStation 3 or Xbox 360 versions of the game. If you start receiving an error message related to IW3sp.exe during gameplay, you can fix the problem but must do so in a very specific way.
Place your "Call of Duty 4" CD-ROM into your computer.
Click "Start." Open the "Computer" folder. Right-click on the "Call of Duty" CD-ROM icon and click "Explore." Locate the file labeled "IW3sp.exe." Drag the file onto your hard drive to make a copy on your computer. Close the window.
Click "Start." Open "Computer" again and then "Program Files."
Open the "Activision" folder and select the "Call of Duty 4 -- Modern Warfare" directory. Open the folder labeled "Zone" and then the folder inside that folder labeled "English." Drag the copy of the IW3sp.exe file you copied to your desktop into this directory. This will replace the corrupted file and allow you to play the game again.