Expansion devices not recognised by Vista

Hi,
I've just done a clean install of Vista Ultimate on a machine that previously ran Windows XP Pro.
Now none of my PCI devices appear to be visible.
Motherboard> Asus P4R800-VM
PCI devices: > Belkin Wireless network adapter, Modem card, EMU0404 Sound card and in the AGP slot I've got a Radeon 9550 256Mb card.
These are all invisible? I've tried installing the drivers, but when I go into Device Manager they're just not there! I am stunned!
Am I missing something? Is there something else I need to do for Vista to detect new hardware?

Thanks