Why won't my video export

I made a short 6 second animation, and when I tried to export as an mp4, it had the pop up that's like "creating swf, creating mov", but adobe media encoder did not open and start converting the video to an mp4. I had "start adobe media encoder immedietly" checked, and I even tried unchecking it and putting it into adobe media encoder myself, but adobe media encoder literally will not open, even if I manually click on it to open. All of my apps are up to date. What is happening and how do I fix it?