Serial.print TX LED question (SOLVED)

Hi, i do some play with code that send serial to the Arduino IDE. as i click on the Serial Moniitor icon, i can see the TX led on the arduino board to start sending the data. BUT, if i only push on the RESET button on the arduino board, there is no transmit LED??? it only start as i click on the Serial Monitor. i was thinking that the Serial Monitor was simply doing a reset when turn on, but then why isn't the arduino sending data after i press the RESET button. Any idea? Thanks in advance

Ok did some more test, The TX LED only flash if the com port is connect to a software. Hyperterminal work also. The arduino still Transmit Data but the led won't flash if the usb port is not connect