I had fits trying to get the Arduino driver to load on my XP Pro laptop. I wrote Jeremy Blum, and he answered in a day or so.He refrenced the page http://arduino.cc/en/Guide/Windows#toc4
, which then gave me the driver file name. For the uno, it is "ArduinoUNO.inf". Once found, I could not get the driver to upload using the driver update manager. I opened the Arduino files and found the file Arduino\Drivers\Arduino MEGA 2560.inf.
I did a drag and drop to the My Documents folder, used the My Documents Folder as the file destination for the hardware driver update Wizard after the selections.. No, not at this time > Install from a list...> Include this location in the search:
C:\Documents and Settings\Owner\My Documents
Bingo it loaded. I hope this helps someone.