please help! can not open sims 4..? already running?

hello! i do not know why my pc keeps doing this but it will not let me open sims. It keeps saying it is already open but I do not have anything else involving sims open?? so i do not really get what the problem is.. i was already having a problem with one of my save files and tried to restart my pc and now it is showing me this everytime i try and open up sims 4 on steam. can anyone help me?? id really appreciate it !! 🙂