I connect 12V to 5v pin on Arduino Duemilanove by acident and it destory board.
Anyone can help me suggestion what i should be replace to fix it.
i think now i burn out my ATMEGA328 and FT232 IC becuase my computer does not recordnize USB anymore.
i don't sure other IC like LM358 still alive.
The ATmega328P is probably destroyed, so remove that. You may find that the USB port is recognized again (maybe...maybe not...) meaning you won't have to replace the FT232.
Depending how long you kept the 12V connected, other components on the board may or may not have been damaged. My guess is replacing the ATmega328P and FT232 will be enough (and maybe even just the ATmega).
Thank you, i test it the ATMEGA and FT232 was gone.
Some of the caps around the regulator might also have been damaged or degraded. It's probably best to just buy a new board or for less $, one of the fine clones from other vendors. Replacing that FTDI chip is not an easy task unless one has the tools and experiance dealing with SMD soldering.