BMW: Cold starting problems, light flicker, model bmw

Question
My car is a 2001 325ci with 45,000 miles. It usually runs great. Then last week, when it sat for 3 days during a snow storm, I tried to turn it over and it wouldn't start. (It was close to turning over.) My husband thinks I may have flooded it. What should I do now? Should I charge the battery? I also had the need maintance soon light flicker on,but then it went out. My oil change is 1500 miles away. Would an O 2 sensory cause this problem? Thanks for your help.

Answer
Sue,
 I will warn you now, but this is not my area of expertise, as I know more about the older BMW's.  Since the weather has been cold, I have received numerous questions about late-model BMW's not starting.  Batteries and Alternators have a hard time when it's cold out, they dont produce as much energy as they did when it was warm.  Being a 2001, it could possibly use a new battery, although I have seen some work fine for 7-8 years if maintained properly.  
 It would be tought to "flood" one of these BMW's, as they are fuel injected, and only allow fuel to be introduced if the engine is spinning. An old carburetted engine is different, as long as you are holding the gas down, it will squirt fuel into the engine and "flood" it.  So that being said, that is out of the question.
 I think your battery is just weak, and being that it was cold it just didn't have enought power to start the engine.  
 An O2 sensor could cause running issues, like a rough idle or flat spots in acceleration, but It should not affect starting.  
 Have your husband grab a good battery from the autoparts store, and with 2 wrenches and 5 minutes he could save alot of money.  Make sure he connects + to + and - to - though (99% of the time RED is the +)

 Hope this helps, I appoligize for lack of knowledge on your vehicle.
 Merry Christmas,
 Josh