Hi.............
can anyone tell me what is the exact driver file for freeduino?
Depends on what model you have and what they use for USB-to-Serial.
My best guess is that they use the same FTDI chip used on the older (pre UNO) Arduino models. For that you can use the FTDI driver included in the Arduino software. To get the latest FTDI Virtual Com Port drivers go to : http://www.ftdichip.com/Drivers/VCP.htm