install a game and run the game

I've been struggling with downloading a game on my computer, and I tried to contact the company costumer service and nobody was able to help me. the game is the sims 4 and im trying to download it on my computer, but everytime i tried to run the game it gives me an error message saying : "unable to start the sims 4 is already running". I don't know what to do at this point. I just need a professional to help me with this, so if you have experience in PC and downloading games and find the source of this problem, please contact me