S!
Marmaduke, easy steps to use the beta patch. Trying to be as clear as possible
1) Go to X:\Users\..\Documents\1c SoftClub\CoD folder\cache\shaders\ and clear it.
2) Run the file integrity check from Steam(right click game in Library -> Properties).
3) Get 7Zip, a free and very good compress/extraction proggie. Install.
4) Download the beta patch, right click and choose Extract here.
5) Copy the Parts and PaintSchemes to the X:\Program Files (x86)\Steam\steamapps\common\CoD folder and replace files/folders when asked.
6) Start game and enjoy
Hopefully works for you.