A couple of months ago, I disabled my Bluetooth device from inside Ubuntu 10 (I forget which version specifically).
I then rebooted into Windows, only to find that the icon was gone. Curious, I went into Device Manager, and saw that there was nothing detected there either... and started panicking quite a bit! No error, no warning, nothing... it was plain gone, as if my computer never even had a Bluetooth module in the first place.
I tried reinstalling the driver, turning the switch on and off, etc., but nothing seemed to work. In my last bit of hope, I went into Ubuntu and was (to my relief) able to turn my Bluetooth back on, and it was recognized again in Windows.
The problem is since gone, and I will not try to reproduce it, but I never figured out the reason:
How could a device be "seen" in one OS, but not the other?