If you reinstalled it twice - the problem, probably, is with your system.
- Try to update your drivers.
- Depending on how psychotic your antivirus is, it could mess with some files' code without even notifying you. Try to add to your antivirus exceptions the archive itself (before downloading it) and the folder where you install the game afterward. [You can do it by adding the folder to your 'exceptions' and then downloading the archive inside that folder. I think.] Then redownload and reinstall.