BMW Repair: 2001 330ci starting problem, cluster displays, high pitch

Question
I have a 2001 330ci with 105,000 miles- vin ju37212.  
It drove perfectly 2 days ago.
I put in in my garage when i got home. I diddn't drive it yesterday. When I tried to start it today, nothing happened..It made a high pitch hummm, then several clicks, and all the lights went on inside, including the dash. Even the headlights work. Some of the lights inside blinked, and the wipers moved. The lights soon go off when the key remains in start position. When the key is removed it hums from the underneath and behind the radio. hope it's not serious. Thanks for some imput.

Answer
Shari, please have the battery checked. Does the car jump start with the under hood jumper terminals (see owners manual if you don't know what I'm talking about). These are symptoms of a bad battery. Battery is in the passenger rear trunk area under that black plastic panel. Look at the top of the negative battery post (black cable) and see if it has a two digit year stamp in it (00 or 01). If it does then it is the original battery. Did the vehicle clock reset? It does when it looses power. You need to check the battery voltage. With the key in the second position (two clicks forward) press and hold the left instrument cluster botton until you get (test 1) Release button and press several times until you get to (test 19) When the cluster displays 'Lock off' press the button again. It should go back to 'test 1'. Again click the button until you get to 'test #9'. Test number 9 will show you system voltage  (125 equals 12.5Volts) A fully charged battery will have 12.6volts in it. If it shows less than 12.0volts then the motor probably won't have enough Voltage and Amperage available to crank the motor over. Once the engine is running and the alternator is again charging the system and battery you should see           130 =13.0volts to 142 =14.2volts if the alternator is working correctly. Please fill out a follow up survey if this helps.
-Evan