(updated)Help on Serial communication between Arduino and PC!!

Worked perfectly means that both mega and PC are working fine

I have updated my problem. still need a lot of helps :slight_smile:

These are contradictory statements, you know. If everything is working perfectly, it's time to quit. If not, the "everything's fine" is not true.

So, which is it? Going back and editing your original post is nor a good idea.