My Bluetooth dongle was natively supported by Windows x64.
So I thought it wouldn't be an issue to let WU install an update to its driver a couple of weeks ago.
But no, it went and broke it.
Hilariously, the device manager said all was fine... but bums was it! The light wasn't flashing on it any more and nothing would connect with it. And of course, there was no way to uninstall it, and by the time I noticed (took me a while because I trust that my phone-sync kind of JustWorks[TM]) I didn't want to System Restore. Driver rollback wasn't supported either... go figure.
So, I delved into C:\windows\inf and sorted by modified date. I found the right inf file and removed that sucka, the uninstalled and replugged the dongle... boom it works again.
So thanks Windows Update, thanks for pushing WHQL certified drivers that break my bluetooth device onto me... no really, thanks.