USB keyboard + vista + sleep

I have a lovely new USB keyboard, but it now stops my vista machine going to sleep. Under event viewer it says that the USB Root Hub resumed the machine from sleep immediately. I’ve tried every combination of picking USB sockets, and tried ticking and unticking the ‘allow this device to wake the PC’ on the hub, the keyboard etc under device manager. Still no joy.
I cant use a usb->ps2 adaptor, the keyboard won’t work with it.
Any ideas? this is driving me nuts.
My PC uses S3 sleep and it normally sleeps just fine.

Turn it off?

Since you tried everything else the problem is obviously with your new keyboard. Vista itself sleeps just fine on (probably) millions of systems with USB keyboards, so there’s no fundamental issue here.

What’s the brand of your keyboard? Are there any custom drivers you might need to install? Is there a built-in USB hub with other devices connected to it?

Your BIOS might have a setting that allows you to pick what can wake your PC up. Mine for instance allows disallowing the USB keyboard and mouse and only letting the power switch wake it.