trouble with arduino uno driver and vista

It´s a desaster…. Please help me….
I have a new Arduino Uno R3. I proceeded „getting started“ on arduino.cc. Everything is ok, when I use a Laptop with Windows 7. Upload works.
On the other Laptop my vista 32 home just finds a „unknown device“ when i plug my arduino in (USB). At first attempt to install the driver (Arduino 1.0 download) the driver cannot be used/found. Vista installed a microsoft driver instead. When I try to install the arduino driver manually, my vista always prompts that i´m using the right driver.
The arduino cannot be uploaded, it cannot be found….
Please help me…
:blush: