randomfeelings - the upnp message is normal, you just don't normally see if for very long as X is supposed to be starting at that point.
Don't know if the bluetooth adaptor really had anything to do with it ... it sounds like X couldn't start. Often when this happens you see the screen periodically blank and come back, each time X tries.
If it is starting now, then perhaps you are fine and can re-add the bluetooth adaptor safely. But if this happens again, you should carefully read through the /var/log/Xorg.0.log file as this will document where X is failing...