I have tried Serial.Println as well - My understanding was that Serial.print would do a new line and Serial.Println would do a new line with carriage return, or is a new line feed different?
Serial.print() adds nothing to your string.
Serial.println() adds a carriage return and a line feed.
Try:
Serial.print("START\r");
or
Serial.print("START\n");
to see which the software actually understands.