I downloaded a file from pushed to insanity (intro machine) and when I opened it on after effect said that it is locked and I will not be able to save it and when I finished editing the file when I go to render it, it does not let me press the button. If it helps I'm using the trial version of after effects.
We have no idea what's going on because you have not provided any details.
Try using the Save As feature and save it to a different location on your computer. Then, specify the output location and render.