A compiled and inferred list of suggestions;
1. The most common and simple reason is you are not running the set up or actual game under
administrator.
From Vista Support
"1. Locate the applications icon or short cut and Right click on it.
2. From the Drop Down Menu select the Run As Administrator option.
3. Now click the application icon or short cut and it should run.
4. When the User Account Control (UAC) message appears enter the appropriate credentials if you are logged on as a standard user, and click the Submit button.
5. If you are the Administrator and UAC is not configured to always require credentials, just Click the Continue button and the application should start."
2. Your
Graphic drivers are not completely updated, The most common drivers used are;
ATI
AMD Graphics Drivers & Software ? Download the latest drivers for your graphics products
NVIDIA
Drivers - Download NVIDIA Drivers
If you are unsure what you are running, Use a program such as Speccy to find out exactly;
Speccy - Standard
Copy your
Graphics Section and paste it into google.
3. You may want to try a
Alternative Download
Cross Fire - Free Online FPS - Cross Fire - Free Online FPS - Home
4. Another common problem; Another program most usually an Anti Virus Program - is changing the functions of the files as they are being installed. Please disable things such as Xfire, and your Anti-Virus Program when installing.
Helpful post on re-installing;
[GAME ERRORS] GUIDE - Performing A Clean Installation Due To Errors - Z8Games
Good luck!