WinXP32 guest on Vista64 Host - No USB devices work

[circuitpro]

I've just upgraded to 3.0.8r53138, and find that no USB devices are working. They are turned on in the SETTINGS, and show up there, but do not function. No USB printer, USB Stick, etc. The VBox Guest Editions have been installed. Am I forgetting something obvious? Thanks very much.

[Perryg]

Did you try a complete reboot?

[circuitpro]

Many times, thanks. If I look at the 'Devices' pull-down from within the Guest, at point at the USB device representing my USB Stick, I get an error message as follows:

"Failed to attach the USB device Sony Storage Media [0100] to the virtual machine WinXP.
USB device 'Sony Storage Media' with UUID {b97da1c9-e015-47f2-8bc9-9909711c01b5} is busy with a previous request.
Please try again later.
Details:
Result Code: E_INVALIDARG (0x80070057)
Component: HostUSBDevice {xxxxx...xxxxx}
Callee: IConsole {xxxxx...xxxxx}"

This sounded a little to me like I should not have plugged in my USB stick until after I had started the Guest OS. So I tried that... then the guest system said "New Hardware Found" and saw the memory stick for about 10 seconds. Then I got a Blue screen of death saying "...Preparing for crash dump." etc. and had to completely power off everything at that point. It does recover, but never changes it behavior.

Interestingly, the USB mouse IS working, but that's all. No external USB printers, etc.

Any input very much appreciated. I read in the User's manual that USB operations are flakey under a Vista64 host, so thought this is probably something that everyone is living with? No?

Thanks.