Just a note - I ran into the same issue with an Arduino Uno SMD edition driver installation on WIndows 7 (64-bit). After installing the driver through the steps provided, I kept getting a Code 10 error (driver will not start or something like that). I went ahead and deleted the COM ports and device in Device Manager (selecting the checkbox to delete the driver software as well), then scanned for hardware changes and the Arduino Uno showed up in the "Other Devices" section.
I went ahead and took screenshots to step through how I was able to get it installed this morning before I head off to work, but the adafruit forum is hating on me this morning and will not let me upload the attachment... I feel like I've been kicked around by functionality that should work this morning, maybe I should call in sick and write this day off already... it's not even 9am yet. heh
Anyway, below is the text from that small install guide in case it proves to be useful for anyone. Sorry the screen shots wont go through.
Install UNO SMD Edition Driver for Windows 7 (64-bit)
After following the instructions for the Arduino UNO driver, I received a Code 10 (driver will not start). After playing around with it a bit, I found that something had not installed correctly. I went ahead and deleted the COM ports (and selected the option to remove the driver from the computer so it wouldn't auto resintall) and then started over.
After scannin gfor new hardware the Arduino Uno was showing up in "Other devices"
1. Right click on the Arduino Uno device in Device Manager and select "Update Driver Software"
2. Select "Browse my computer for driver software" and then "Let me pick from a list of drivers on my computer"
3. Click "Next" on the "Select your device's type from the list below", leaving "Show All Devices" selected (default) and then click on "Have Disk"
4. Select "Browse" from the Install from Disk menu and navigate to your arduino software installation directory and go into drivers
(i.e. C:\Development\arduino-0023\drivers in my case)
You should see Arduino UNO in the file list. Highlight it and click "Open"
5. Click "Ok" at the install from Disk menu and hopefully "Communications Port" shows up now on the "Update Driver Software - Arduino Uno" box. Leave that highlighted and click "Next"
Note: I received a security warning which I had select "Install driver anyway"
6. The driver now installs and for me fixed the problem. The Arduino UNO now shows up as a COM port (COM4). It doesn't say it's an Arduino Uno, just a COM port. To verify, look at the Manufacturer in the COM port properties and it should say something like http://www.arduino.cc
The last thing I did was go into the COM Port properties and change the baud rate to 115200.
After that I was able to select the new COM port in the Arduino application, select the correct board type in "Tools". I compiled and successfully uploaded the sketch. Yay!