Arduino Uno code 10

So, I've looked around the forums, and I haven't found an answer to my particular problem. I have an arduino uno, I just got it, it's the second one I've purchased and I can't get it to work. I've downloaded the drivers and software from this site, plugged the board in and get... almost nothing. The ON button turns green, there is a red light by the "L", it makes the USB happy sound, but nothing installs. I saw that the issue seems to be Windows 7, so followed the driver installation manually, and no matter what folder I select, Windows doesn't find anything. I tried just Arduino.inf, and it will install, give me a com port, and immediately say the device cannot start (code 10).

THINGS I've TRIED:

  1. I tried manually installing the .inf file, which leads to the code 10
  2. I tried installing as a usb serial, and get the code 10
  3. I tried installing as a com port, and it won't accept the driver
  4. I've tried on a Windows Vista and a Windows 7 computer
  5. I've tried different USB cables

The odd part is I've given the first one to a friend, he plugged his into a windows 7 machine and it just worked. No real finagling or anything like that, just up and worked. On the little chip on the board, it says

Atmel or Amtel
Mega328P
AU1508

I'm not sure if that's helpful but I've seen that info asked for. Another note is I've only gotten the Arduino designation after I've messed with it for a long time, usually it just says usb 2.0 serial or something like that until I install some driver or another using the "Choose from a list of devices/ have disk" method.

Thanks in advance for any help you can give me, I really want to see what these lil guys can do.

What does it say on the second largest chip on the board, the one near the USB port? Should be either mega16u2 (use arduino drivers), ch340g (use ch340g drivers), or ft232 (use ftdi drivers) - that's what determines which drivers you need.