I own a 2004 Audi A6 2.7T. Out of the blue my car will not start. I know that all fluids are filled. The battery is good and my starter is good and tries to turn over the engine however it will not start. There is fuel in the gas tank. I'm guessing it is either the fuel pump, fuel filter, or maybe even a bad ignition coil. The engine light is on. Has anybody ran across this problem?

Its very cold where I live but I have had no problems in the past with starting it cold. When this problem started I was able to start it but it would have problems staying running. This has progressed to the point where it will not start at all. Any suggestions?? Your help is very appreciated.