Please do post your dxdiag for us to see, also we'll need to know more about your PC's specs. In the mean time I recommend that you open your PC origin client, go to your game library and right click the BF3 icon and select the "repair" option. Allow the repair to run and after try to play BF3 again to see if that solves your problem.
Are you receiving any error messages or error codes when the game won't work?
Also ensure that your drivers are all up to date via Windows update and update your GPU drivers as well.
I have already tried repairing it several times, it did not fix it at all, not even for a moment
My processor is an i5 3570k 3.40 GHz, 16 GB RAM, Nvidia Geforce GTX670 graphic card.
Here is my DxDiag, cant upload it here so i will provide a link for it
