WMDC not recognising WM5 Device

Hi
recently bought a laptop preinstalled with Vista Home Premium.
One major snag. It refuses to even see my WM5 device (an HTC Prophet based
phone).
I have installed Windows Mobile Device Centre, I have installed the update,
I have turned off all firewalls. I then connect my (turned on) Windows
Mobile 5 phone via USB.

And nothing happens.
My laptop does not see the device, it does not acknowledge anything is
connected, it does not try and install anything. Nothing happens at all.

My XP desktop has has no problem seeing my phone.

Any ideas on how to get a WM5 device to work on Vista?