This guide will tell you how to Clear & Reinstall Shaders Cache in Modern Warfare 2 Beta. Go through the guide and follow the simple instructions to do so.
First, you have to open the game, then go to settings and click on the Graphics tab. Click on Display on the top of your screen, scroll down, and find Restart Shaders Optimization.
The next thing you will need to do is click on it and it will start restarting the shaders optimization and it will delete all the shade cache. Once it completes, you have to restart the game and hopefully, it will fix your graphics issue.