Did the things Tom suggested help? Please let us know. Also please let us know which assignment it is. There is another case in which a student sees no submit button on C5 W1 A1, but then on the other two Week 1 assignments (C5 W1 A2 Dinosaur Names and C5 W1 A3 Jazz Improvisation) the submit buttons were there. If it is W1 A1 in your case also, please try W1 A2 and W1 A3 and see if the button appears there.