Same problem on two 'puters....one is Windows 7, the other Vista. Anyway..the install instructions read...
Look under Ports (COM & LPT). You should see an open port named "Arduino UNO (COMxx).
This does not happen with either computer.
They both show a new "unrecognized device" when I plug in the Arduino.
So, going with that...I can find the .inf file with windows explorer, but when using the device manager....I only get as far as "drivers"....and it will not show any of the driver choices that I can see when using explorer.
I thought I'd at least be loading 'blink" tonight....can't even get started!!