Bluetooth deactivated through Windows 7 and then returned to Ubuntu:

~$ hciconfig
--- (returned nothing at all)

~$ lsmod | grep bluetooth
bluetooth             247324  10 bnep,rfcomm

~$ lsusb | grep Bluetooth
Bus 003 Device 005: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0 Hub (part of BCM2046 Bluetooth)

# The LED is off and there is no bluetooth-symbol in the top bar.
# System settings » Bluetooth says "no bluetooth adapters found"