by stopping the installer from executing the game's installation code.
Data Execution Protection is a useful safeguard against virus infections, but it can be a nuisance in situations like yours. Fortunately you can take control of the situation easily enough:-
1. Open the System by clicking the Start button , clicking Control Panel, clicking System and Maintenance, and then clicking System.
2. Click Advanced System Settings. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3. Under Performance, click Settings.
4. Click the Data Execution Prevention tab, and then click Turn on DEP for all programs and services except those I select.
Now select the check box next to the game and then click OK.
If the game isn't shown in the list, click 'Add'. Then browse to the Program Files folder, find the executable file for the program (it will have an .exe file extension), and click 'Open'.