Make sure that your Windows user account has Administrator privileges, and that User Account Control (UAC) is disabled in your operating system. To do this, go to Start -> Control Panel -> User Accounts and Family Safety -> User Accounts -> Change User Account Control settings. Move the slider to the lowest position ("Never notify") and click OK.
Afterwards, make sure to always launch the game with “Run as Administrator”.
If this doesn't help, try reinstalling the game by using "Run as Administrator" on the installer itself.