Serial Port Greyed Out on Arduino Program (Duemilanove)

[u]The Issue:[/u]

Over the course of about 15 minutes of me being away from my computer, I came back to my serial port being greyed out. I hadn't installed or changed any drivers to my knowledge and to confirm this, I did a system restore to yesterday. I have tried 2 different boards AND connecting reset to GND and Digital 1 to Digital 2 with jumpers. The boards are also not discovered on other various computers. I am using Windows 7 32 bit and am able to recognize other hardware such as memory sticks etc. but the boards are not being recognized AT ALL and there is no changes under the device manager when the board is disconnected and reconnected. Any suggestions are helpful and methods of troubleshooting for this issue are welcomed. I have also tried reinstalling Arduino with the FTDI drivers.

Edit: The board is also receiving power if anyone is it is not the USB cable/port. It also works on another computer with very similar specs and the EXACT same operating system and the EXACT same version of Arduino.

Hi. This sounds like your FTDI chip is not being detected. Can you look into your Device Manager and try to find the USB Serial Port under 'Ports (COM & LPT)'?

Bump: I think I burned the FTDI chip on my Arduino. I've searched causes on google but am unsure of what could have caused the FTDI chip to burn out. I was using the 3V3 along with VIN and GND attached to a 9V battery to externally power the arduino along with a ChipCorder and 8-ohm speaker. The computer no longer recognizes the FTDI chip. Any suggestions to repair the board? The pins are super small and would be difficult to desolder. Would replacing the entire board be a cheaper option?

I was using serial communication to input the current time and target time. Could this possibly overload the FTDI chip or did I burn it out from an overload in current from the 3v3?

In the past probably the most frequent cause of FTDI failures was drawing more then the 50ma max rating of the 3.3v pin. The uno board uses a on-board 3.3vdc regulator instead and is much more forgiveing of over drawning current on that pin.

Replacing the FTDI chip is difficult if one doesn't have the experiance and tools needed for SMD removal and replacement. I would just buy another board. Your existing board most likely would still be useful by developing code on the new board and then just move the 328p chip to the old board, as long as it's not using serial commands.