Scragbat

I also have Ultimate x64 (SP1 + latest updates) and bought a second-hand wired 360 controller (sold my 360 months ago!). All I had to do was plug it into a USB slot and it just started working. I didn't have to download any software for it. I'm pretty sure Vista did that automatically (icon on the taskbar/systray telling me hardware installing), I think Vista may have downloaded additional drivers for it but I didn't have to do anything manually.

All I can tell you is that SP1 was installed prior to plugging the controller in and I was connected to the Net, it popped up on the taskbar/systray almost immediately saying it was installing...

Hope you sort it. It's the perfect gamepad for the PC. Using it on GRID at the moment...