I have a 01 X5 and this morning It wouldn't start up at all, but yesterday it was running perfectly. The battery was replaced by BMW a year and two months ago, so I don't think its the battery, but could it be the alternator, and is there any way to check, I just hear a clicking when I try to start it, and The lights go on when I open the doors.

Did you try to jump it with another car? If it starts, then your battery is weak and could possibly be not charging (alternator). There are a few problems it could be, but I would start there.

Also, some auto parts stores have battery testers to see if your battery is good.

I Tried to start it today by Jump starting it, But I had no response at all, what else do you guys think it could be?

Where did you hook up the jumper cables? Check the battery terminals and clean/tighten them.

The Battery terminals were clean, and they were also tight, and I connected it to the positive and negative in the engine compartment.

Okay... so I went to Autozone with the battery and I went to get it charged, but they said that the battery wasn't charging completely, and they did a battery test, and concluded that the battery was bad, then they told me I should take a battery from another car and see if it starts, then I could determine if it was the alternator or not, so before I do that, I was wondering, if the battery is dead, does BMW have a warranty for their batteries since it was changed June 2007. Also I can't find the battery for it anywhere, I checked Napa, Autozone, Murrays, and Carquest, NTB, Sears and None of them had it, NTB buys them from Napa, and Napa doesn't have it in their computer. Does anyone know what brand the BMW batteries are.

Now I just reinstalled the battery, and all the gauges come up, but it still won't start,

I have a Motorola IHF1000 that is Handsfree Bluetooth, and that's what BMW told me was draining the battery, yet It turns off when the ignition is off, so I think BMW might be trying to just get me to pay for more than just a battery failure.

Okay.... I went to BMW and Got it diagnosed and they told me that it was my bluetooth handsfree set from Motorola, and that my Final stage Blower resistor was draining the battery. Would these symptoms really cause the problems they stated.