I recently got a arduino nano after only using unos but I can not get it to show up on the serial port but the power LED and the transmit LED lights up at first then goes away, I tried this tutorial, http://www.arduino.cc/en/Tutorial/ArduinoISP, but it didnt seem to work. I would love any help with this problem!!!!!! 
Perhaps you need to load the drivers for whatever USB-to-serial chip the board has. Look with a magnifying glass at the chip on the underside of the board, and download and load the drivers for that chip.
This worked! Thank you for your help!