My Bluetooth Stack Seems To Have Vanished

As you know I quad boot and this is happening in all my OS's for some unknown reason. As it first happened in Vista, that's why I'm asking here.

Everything was working fine as usual until I decided this morning that it was about time I looked at my Sandisk Cruzer Contour U3 drive and updated it's software.

Normally this is routine. however this time it caused Vista to immediately reboot. Since then my Microsoft Wireless Entertainment Desktop 8000 KB & Mouse plus dongle may as well not exist - to make matters worse, in all my OS's. Thank God I keep my trusty old M$ basic optical mouse and internet keyboard connected just in case.

I've tried unplugging/replugging the dongle, rebooting etc. etc. but it's as if Windows doesn't want to know about it. There is nothing in Device Manager and when I scan for hardware changes it finds nothing.

Why, after months of trouble-free use, would this suddenly start?

I will admit that on occasion in the past inserting the U3 drive has caused a reboot and has even caused the mouse and keyboard to disconnect, but that has always been temporary and has remained a mystery to me and Bill Gates (I presume because M$ are useless when I ask them).

I'm hoping that. after a lengthy rest, i.e. turned off, Windows will forgive whatever transgression I'm guilty of, and decide to "see" the darn thing.

Addendum: I gave it a long rest while I went to shave an shower. Remembered that I had an identical MSFT BT 3.0 dongle from another KB and MOuse set. Tried that. Windows installs drivers but it doesn't show up in Device Manager, still....grrrrrrrr!
Same in XP, Vista and Windows 7 by the way.

Next thing I suppose is to uninstall/reinstall the software and see if that makes Windows think again.

Forget it, emergency over...not sure if it was the new dongle or reinstalling the software (Intellipoint/type), or both, that did it but it's now working in all my OS's after at least 2 million reboots, or so it seemed....!

The question iks why would a U3 USB drive cause such a mess in the first place?