Audi Repair: Audi A6 wagon doesnt start, audi a6 quattro, audi a6

Question
I recently purchased an Audi A6 Quattro Wagon, everything was fine until one night a few nights ago, it snowed and was very cold. The next morning I tried to start car. The engine did not start, but all I heard when I turned the key was a loud studdering noise, I believe it could be the battery because the night before the indicator was telling me the battery was low, Im not sure if the battery is the problem or somthing else. It would be awesome if someone could help me out.

Answer
Sounds like the relay is not being energized enough to start the engine, and it is just clicking on and off.  This is typical of a failing or low battery.  Verify this if it starts with a second battery or 'jump-start'  Always connect the positive wire of the jump battery first, and disconnect it last.  Positive goes to positive, ground (negative) goes to ground (negative).  If you saw a warning light for a low battery, is your charging system working OK?  Let me know how you get on,  Jan