BoardUno. Overview The Arduino Uno is a microcontroller board based on the ATmega328 (datasheet).
It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip.
Reference. UnoDriversWindowsXP. This is a guide to getting the Uno working under Windows XP after the operating system has tried but failed to install the drivers.
For more information, see: getting started with Arduino on Windows. Step-by-step screenshots created by Pluggy. Tutorials.