The links above doesn't solve the problem for me.
I try to figure out how to make my arduino nano work with Windows 8 x64.
As recommended, I have downloaded the FTDI Drivers (http://www.ftdichip.com/Drivers/VCP.htm
) as I found with a Google search but no... It doesn't work.
I have tried the previous version of the driver (2.08.28) and the new one (2.08.30) but even if the board is correctly connected and all seems good in the system panel, upload of sketches doesn't work.
I've tried différent settings (like changing baud rates) but I don't have more success...
I've checked that's the board is not faulty with a linux laptop (linux Mint) and all is good. I've succefully uploaded a sketch and serial communication works.
It seems obvious to me that's it's windows 8 (driver) problem...
[EDIT] : Here a working solution for the Nano : http://forum.arduino.cc//index.php?topic=194534.0
Downgrade the driver to the 2.08.24 ! (not available on the FTDI WebSite)