bluetooth not available

I upgraded OS to 10.8.5 and lost my Bluetooth mouse. Menu bar states "Bluetooth not available". There is no Bluetooth in System Prefeferences. Application Bluetooth File Exchange is 4.1.7. When opened it states no hardware is found. When download/activating Bluetooth 2.0.1, I get a statement that 'this computere does not need this upddate. This text is written on a Bluetooth Keyboard.

Any suggestions?